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This article details the evolution of maritime security from the perspective of its impact on the historical architecture of sea space. It argues that, as the fundamental unit of governance, zoning provides keen insight into the mechanics of maritime security. The article observes that Britain's Hovering Acts in the late eighteenth century represent the earliest example of modern zonation at sea and that they exhibit a shift from early modern territorial claims based on imperium and dominium. The article explores the way these hovering zones shaped the rationale underlying contemporary maritime security. It finds that maritime security has effectively relegated national security to a minor spatial belt of state power, while elevating non-traditional understandings of security to the level of global existential threat. The future of maritime security is under construction. Increasingly segmented by interconnecting, overlapping, multi-functional zones that seek to regulate all free movement and usage of the sea, security developments are reorganizing the maritime sphere. Nonetheless, the article argues, despite the novelty of this development, a historical military logic persists in new formations of security-oriented practices of maritime governance. [ABSTRACT FROM AUTHOR]

The paper forms a Foucauldian analysis of police reforms in Montenegro. Drawing on interviews with police officers at all ranks in 2004, undertaken as reform was commencing, and on interviews undertaken in 2010, after Montenegro's independence, the paper explores the biopolitics of liberalisation. The paper aims to demonstrate norms of internal security liberalisation that operate beyond a legal understanding of state power. It illustrates the operation of a rule of police that produces norms conducive to the governance of a dynamic market state. It argues that the rule of police subsists within but also subverts the rule of law and the human rights approach to democratic development. [ABSTRACT FROM AUTHOR]

This article explores maritime protection zones (MPZ), which are being created in the territorial waters of a number of European states. Through the work of Gaston Bachelard and Peter Sloterdijk, the article analyses maritime zonation as a paradigmatic global security mechanism. It examines how maritime spatial planning seeks to reconfigure sea-space into multi-dimensional spheres of predictability and rationality. These processes, it proposes, seek to routinize the use of sea-space and reconcile tensions between the governance of land and sea, and between fixed infrastructure and mobile capital flows. The political and economic redistribution at stake in the construction of a global network of vast maritime zones, which act as hubs of wealth creation and environmental management, creates further tensions where commercial and military security imaginaries meet local and ecological interests. The article traces the ontology of multi-dimensional zonation and concludes that space which emerges from a pluralist and less anthropocentric understanding of the maritime would provide more effective security. [ABSTRACT FROM AUTHOR]

This paper examines power relations along the African coast of the Indian Ocean in terms of space and time. Spatial strategies, it argues, are swiftly emerging through zoning mechanisms which territorialise the governance of ocean space. These strategies can supplement and disrupt more traditional temporal strategies, which facilitate speed and freedom of movement for commercial and military traffic. The article focusses on the US proposition to provide maritime security sector reform to African coastal states as a form of temporal strategy designed to shape new zoning practices in favour of freedom of movement. The paper concludes by arguing that the US strategy implies a policing approach that generates maritime surveillance capacities along land–sea lanes of communication. It contrasts this surface form of knowledge with the need for African coastal states to generate the sort of oceanographic data presently undergirding the emerging blue economies of Europe. [ABSTRACT FROM AUTHOR]

This article introduces reasonable force as ontological to the performance of late modern police power. It argues that policing emerged through reasonable force as an innovation of military power and as a supplement to legal power. The article tracks the development of reasonable force in late modern policing through to its emergence as a vanguard strategy of post-Cold War global governance. Police power, the article finds, has transformed traditional sovereign power relations to incorporate governmental power. It finds policing power to be an expansive reforming force that exhibits a dynamic capacity to provide relational coherence to multi-layered policing constellations from the local to the global. [ABSTRACT FROM PUBLISHER]

Abstract: Voltage-dependent potassium channels (Kv) are involved in various cellular signalling processes by governing the membrane potential of excitable cells. The cytosolic face of these α subunit-containing channels is associated with β subunits that can modulate channel responses. Surprisingly, the β subunit of the mammalian Kv1 channels, Kvβ2, has a high level of sequence homology with the aldo–keto reductase (AKR) superfamily of proteins. Recent studies have shown that Kvβ2 can catalyze the reduction of aldehydes and, most significantly, that channel function is modulated when Kvβ2-bound NADPH is concomitantly oxidized. As a result, the redox chemistry of this subunit is crucial to understanding its role in K+ channel modulation. The present study has extended knowledge of the substrate profile of this subunit using a single turnover fluorimetric assay. Kvβ2 was found to catalyse the reduction of aromatic aldehyde substrates such as 2, 3 and 4-nitrobenzaldehydes, 4-hydroxybenzaldehyde, pyridine 2-aldehyde and benzaldehyde. The presence of an electron withdrawing group at the position para to the aldehyde in aromatic compounds facilitated reduction. Aliphatic aldehydes proved to be poor substrates. We devised a simple HPLC-based assay to identify Kvβ2 reaction products. Using this assay we showed, for the first time, that Kvβ2 can catalyze a slow aldehyde dismutation reaction using 4-nitrobenzaldehyde as substrate and have identified the products of this reaction. The ability of Kvβ2 to carry out both an aldehyde reduction and a dismutation reaction is discussed in the light of current thinking on the role of redox chemistry in channel modulation. [Copyright &y& Elsevier]

This article forms a critique of security sector reforms implemented in Albania and Montenegro between 2000 and 2007 by and on behalf of the European Union. It argues that within these reforms it is possible to discern a tension between a more holistic development approach and a security-based approach that is top-down and largely founded on the self-referential security concerns of the European Union. Drawing on research conducted by the author in Albania and Montenegro, the article utilizes public surveys to point out the distance between internal security reforms funded by the EU and the everyday security concerns of residents living in ineffectively policed states. The article concludes that a security-first agenda has slipped into the EU's aim to create an area of 'freedom, security and justice'. Thus, while the rims of the Western Balkans are being secured, lack of reform in the interior hampers the socio-economic development and democratization of states engaged in the EU enlargement process. [ABSTRACT FROM AUTHOR]

The present article analyses the role of the District Policing Partnership Boards conceptualized by the Patten Report as a pivotal aspect of policing reform in Northern Ireland. It argues that, as originally envisaged, these Boards possessed a participatory capacity to transform rigid institutionalized relations of power between state and society. In outlining their potential the article aims to highlight the difference between traditional consultation mechanisms and more communicative-based participatory policing. The article analyses the reasons why this more radical model was rejected and examines the impact of this on the operation of District Policing Partnerships. It concludes that the consultative mechanisms that emerged have so far contributed little to the structural transformation of police-society relations in Northern Ireland. [ABSTRACT FROM AUTHOR]

Abstract: Horseradish peroxidase (HRP) has long attracted intense research interest and is used in many biotechnological fields, including diagnostics, biosensors and biocatalysis. Enhancement of HRP catalytic activity and/or stability would further increase its usefulness. Based on prior art, we substituted solvent-exposed lysine and glutamic acid residues near the proximal helix G (Lys 232, 241; Glu 238, 239) and between helices F and F′ (Lys 174). Three single mutants (K232N, K232F, K241N) demonstrated increased stabilities against heat (up to 2-fold) and solvents (up to 4-fold). Stability gains are likely due to improved hydrogen bonding and space-fill characteristics introduced by the relevant substitution. Two double mutants showed stability gains but most double mutations were non-additive and non-synergistic. Substitutions of Lys 174 or Glu 238 were destabilising. Unexpectedly, notable alterations in steady-state V m/E values occurred with reducing substrate ABTS (2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid)), despite the distance of the mutated positions from the active site. [Copyright &y& Elsevier]

Abstract: The enzyme horseradish peroxidase has many uses in biotechnology but a stabilized derivative would have even wider applicability. To enhance thermal stability, we applied consensus mutagenesis (used successfully with other proteins) to recombinant horseradish peroxidase and generated five single-site mutants. Unexpectedly, these mutations had greater effects on steady-state kinetics than on thermal stability. Only two mutants (T102A, T110V) marginally exceeded the wild type''s thermal stability (4% and 10% gain in half-life at 50°C respectively); the others (Q106R, Q107D, I180F) were less stable than wild type. Stability of a five-fold combination mutant matched that of Q106R, the least-stable single mutant. These results were perplexing: the Class III plant peroxidases display wide differences in thermal stability, yet the consensus mutations failed to reflect these natural variations. We examined the sequence content of Class III peroxidases to determine if there are identifiable molecular reasons for the stability differences observed. Bioinformatic analysis validated our choice of sites and mutations and generated an archetypal peroxidase sequence for comparison with extant sequences. It seems that both genetic variation and differences in protein stability are confined to non-helical regions due to the presence of a highly conserved alpha-helical structural scaffold in these enzymes. [Copyright &y& Elsevier]

This article examines proposals for the reform of the relationship between internal security and state-society relations in Northern Ireland and finds a divergence from the usual liberal package of police reforms. These proposals embraced the political nature of security provision and aimed to create authentically democratic institutions endowed with sufficient power to contest the state's control over the monopoly of force. Through a Habermassian lens, the research analyses the emancipatory potential of these proposals, and examines the reasons why they were rejected in favour of a state-centric, liberal model that did not deliver the structural transformation of police-society relations sought by the people of Northern Ireland. [ABSTRACT FROM AUTHOR]

Abstract: Horseradish peroxidase (HRP) is a commonly used enzyme in many biotechnological fields. Improvement of HRP stability would further increase its potential application range. In the present study, 13 single- and three double-mutants of solvent exposed, proximal lysine and glutamic acid residues were analysed for enhanced H2O2 stability. Additionally, five single- and one pentuple-consensus mutants were investigated. Most mutants displayed little or no alteration in H2O2 stability; however, three (K232N, K241F and T110V) exhibited significantly increased H2O2 tolerances of 25- (T110V), 18- (K232N), and 12-fold (K241F). This improved stability may be due to an altered enzyme-H2O2 catalysis pathway or to removal of potentially oxidisable residues. [Copyright &y& Elsevier]

Based on research undertaken in southern Serbia following the introduction of multi-ethnic policing units, this article examines the pluralist intentions behind attempts to democratize security through community-oriented policing (COP). It details the achievements and the limitations of attempts to institute multi-ethnic policing as a foundational strategy for COP. Evidence is presented that the reforms did not sufficiently empower local actors over centralized institutions. The article illustrates the limitations of COP, arguing that de-securitization requires the creation of spaces wherein the local order being maintained by a locally accountable police is open to deliberation. [ABSTRACT FROM AUTHOR]

Background: Horseradish Peroxidase (HRP) plays important roles in many biotechnological fields, including diagnostics, biosensors and biocatalysis. Often, it is used in immobilised form. With conventional immobilisation techniques, the enzyme adheres in random orientation: the active site may face the solid phase rather than bulk medium, impeding substrate access and leading to sub-optimal catalytic performance. The ability to immobilise HRP in a directional manner, such that the active site would always face outwards from the insoluble matrix, would maximise the immobilised enzyme's catalytic potential and could increase HRP's range of actual and potential applications. Results: We have replaced arginine residues on the face of glycan-free recombinant HRP opposite to the active site by lysines. Our strategy differs from previous reports of specific HRP immobilisation via an engineered affinity tag or single reactive residue. These conservative Arg-to-Lys substitutions provide a means of multipoint covalent immobilisation such that the active site will always face away from the immobilisation matrix. One triple and one pentuple mutant were generated by substitution of solvent-exposed arginines on the "back" of the polypeptide (R118, R159 and R283) and of residues known to influence stability (K232 and K241). Orientated HRP immobilisation was demonstrated using a modified polyethersulfone (PES) membrane; the protein was forced to orientate its active site away from the membrane and towards the bulk solution phase. Mutant properties and bioinformatic analysis suggested the reversion of K283R to improve stability, thus generating two additional mutants (K118/R159K and R118K/K232N/K241F/R283K). While most mutants were less stable in free solution than wild type rHRP, the quadruple revertant regained some stability over its mutant counterparts. A greater degree of immobilisation on CNBr-activated Sepharos™ was noted with increased lysine content; however, only marginal gains in solvent stability resulted from immobilisation on this latter matrix. Conclusion: Directional, orientated, immobilisation of rHRP mutants onto an activated, modified polyethersulfone membrane has been achieved with excellent retention of catalytic activity; however, re-engineering of acceptable stability characteristics into the "immobilisation mutants" will determine their applicability in diagnosis and biosensor development. [ABSTRACT FROM AUTHOR]

Abstract: Comparison of bioinformatic data is a common application in the life sciences and beyond. In this communication, a novel Java based software tool, ProteinParser, is outlined. This software tool calculates a detailed consensus, or most common, amino acid at a given position in an aligned protein set, whilst also generating a full consensus protein FASTA output. A second application of this software tool, computing a consensus amino acid given a tolerance threshold, is also demonstrated. The phytase and the common bacterial β-lactamase proteins are analysed as ‘proof of concept’ examples. Consensus proteins, as generated by ProteinParser, are regularly utilised in the selection of residues for protein stabilisation mutagenesis; however, this widely applicable software tool will find many alternative applications in areas such as protein homology modelling. [Copyright &y& Elsevier]

Horseradish and soybean peroxidases (HRP and SBP, respectively) are useful biotechnological tools. HRP is often termed the classical plant heme peroxidase and although it has been studied for decades, our understanding has deepened since its cloning and subsequent expression, enabling numerous mutational and protein engineering studies. SBP, however, has been neglected until recently, despite offering a real alternative to HRP: SBP actually outperforms HRP in terms of stability and is now used in numerous biotechnological applications, including biosensors. Review of both is timely. This article summarizes and discusses the main insights into the structure and mechanism of HRP, with special emphasis on HRP mutagenesis, and outlines its use in a variety of applications. It also reviews the current knowledge and applications to date of SBP, particularly biosensors. The final paragraphs speculate on the future of plant heme-based peroxidases, with probable trends outlined and explored. [Copyright &y& Elsevier]

In this introduction to a special section of the September 2019 issue of International Affairs , we revisit the main themes and arguments of our article 'Beyond seablindness: a new agenda for maritime security studies', published in this journal in November 2017. We reiterate our call for more scholarly attention to be paid to the maritime environment in international relations and security studies. We argue that the contemporary maritime security agenda should be understood as an interlinked set of challenges of growing global, regional and national significance, and comprising issues of national, environmental, economic and human security. We suggest that maritime security is characterized by four main characteristics, including its interconnected nature, its transnationality, its liminality—in the sense of implicating both land and sea—and its national and institutional cross-jurisdictionality. Each of the five articles in the special section explores aspects of the contemporary maritime security agenda, including themes of geopolitics, international law, interconnectivity, maritime security governance and the changing spatial order at sea. [ABSTRACT FROM AUTHOR]

The article discusses performative politics that challenges philosopher Peter Sloterdijk’s pseudonism. It questions Sloterdijk’s understanding of democracy and situating it in relation to some of Sloterdijk’s recent and controversial political activities. It is opined that Sloterdijk’s claim of authenticity is his unacknowledged pseudonym through which he attempts to revive, re-empower and render authentic the noble lie for the post-truth age.

The role of the redox state of Kvβ subunits in the modulation of Kv1 potassium channels has been well documented over the past few years. It has been suggested that a molecule that binds to or inhibits the aldo-keto reductase activity of Kvβ might affect the modulation of channel properties. Previous studies of possible modulators of channel activity have shown that cortisone and some related compounds are able to physically dissociate the channel components by binding to a site at the interface between α and β subunits. Herein, we describe some new inhibitors of rat brain Kvβ2, identified using an assay based on multiple substrate turnover. This approach allows one to focus on molecules that specifically block NADPH oxidation. These studies showed that, at 0.5 mM, 3,4-dihydroxphenylacetic acid (DOPAC) was an inhibitor of Kvβ2 turnover yielding a ∼40–50% reduction in the aldehyde reductase activity of this subunit. Other significant inhibitors include the bioflavinoid, rutin and the polyphenol resveratrol; some of the known cardioprotective effects of these molecules may be attributable to Kv1 channel modulation. Cortisone or catechol caused moderate inhibition of Kvβ2 turnover, and the aldo-keto reductases inhibitor valproate had an even smaller effect. Despite the importance of the Kv1 channels in a number of disease states, there have been few Kvβ2 inhibitors reported. While the ones identified in this study are only effective at high concentrations, they could serve as tools to decipher the role of Kvβ2 in vivo and, eventually, inform the development of novel therapeutics. [ABSTRACT FROM AUTHOR]

Recent studies in this laboratory showed that an extracellular cutinase from A. mediterranei (AmCut) was able to degrade the plastics polycaprolactone and polybutylene succinate. Such plastics can be slow to degrade in soils due to a lack of efficient polyester degrading organisms. AmCut also showed potential for the biocatalytic synthesis of esters by reverse hydrolysis. The gene for AmCut has an upstream leader sequence whose transcript is not present in the purified enzyme. In this study, we show using predictive modelling, that this sequence codes for an N-terminal signal peptide that directs transmembrane expression via the Sec secretion pathway. E. coli is a useful host for recombinant enzymes used in biocatalysis due to the ease of genetic manipulation in this organism, which allows tuning of enzymes for specific applications, by mutagenesis. When a truncated GST-tagged AmCut gene (lacking its signal peptide) was expressed in E. coli, all cutinase activity was observed in the cytosolic fraction. However, when GST-tagged AmCut was expressed in E. coli along with its native signal peptide, cutinase activity was observed in both the periplasmic space and the culture medium. This finding revealed that the native signal peptide of a Gram-positive organism (AmCut) was being recognised by the Gram-negative (E. coli) Sec transmembrane transport system. AmCut was transported into E. coli's periplasmic space from where it was released into the culture medium. Surprisingly, the presence of a bulky GST tag at the N-terminus of the signal peptide did not hinder transmembrane targeting. Although the periplasmic targeting was unexpected, it is not unprecedented due to the conservation of the Sec pathway across species. It was more surprising that AmCut was secreted from the periplasmic space into the culture medium. This suggests that extracellular AmCut translocation across the E. coli outer membrane may involve non-classical secretion pathways. This tuneable recombinant E. coli expressing extracellular AmCut may be useful for degradation of polyester substrates in the environment; this and other applications are discussed. [ABSTRACT FROM AUTHOR]

This mixed-methods, investigative case study explores the experience of a virtual learning environment (VLE) change and its effect on the use of digital learning tools specifically, and teaching practice more generally, for chemistry lecturers at TU Dublin (Ireland) prior to pandemic of the coronavirus disease COVID-19. Initially, a questionnaire examined the different teaching identities the participating lecturers might have and how they relate to the literature. These identities were examined under the following themes: sense of achievement, motivational factors for innovation, innovation positioning, as well as social and organizational factors influencing the decision making. A visual approach of representing the questionnaire data, termed 'Lecturer Landscapes', was developed which uncovered new trends based on the biographical descriptors of the research population. Subsequent interviews led to a more detailed investigation of the themes noted in the questionnaire and the Lecturer Landscapes to more holistically capture the professional identity of each respondent. The lens of experience during a VLE change was used to frame each respondent's professional identity in context. Overall, a VLE change does not have to effect teaching practice and can be experienced as a positive change in teaching and learning. It was also noted that innovation can only occur when specific, and individual, needs and problems are addressed and when personal development is promoted by intrinsic, rather than extrinsic, motivational factors. [ABSTRACT FROM AUTHOR]

-glucosidases are a class of enzyme that are widely distributed in the living world, with examples noted in plants, fungi, animals and bacteria. They offer both hydrolysis and synthesis capacity for a wide range of biotechnological processes. However, the availability of native, or the production of recombinant β-glucosidases, is currently a bottleneck in the widespread industrial application of this enzyme. In this present work, the production of recombinant β-glucosidase from Streptomyces griseus was optimised using a Design of Experiments strategy, comprising a two-stage, multi-model design. Three screening models were comparatively employed: Fractional Factorial, Plackett-Burman and Definitive Screening Design. Four variables (temperature, incubation time, tryptone, and OD600 nm) were experimentally identified as having statistically significant effects on the production of S.griseus recombinant β-glucosidase in E. coli BL21 (DE3). The four most influential variables were subsequently used to optimise recombinant β-glucosidase production, employing Central Composite Design under Response Surface Methodology. Optimal levels were identified as: OD600 nm, 0.55; temperature, 26 °C; incubation time, 12 h; and tryptone, 15 g/L. This yielded a 2.62-fold increase in recombinant β-glucosidase production, in comparison to the pre-optimised process. Affinity chromatography resulted in homogeneous, purified β-glucosidase that was characterised in terms of pH stability, metal ion compatibility and kinetic rates for p-nitrophenyl-β-D-glucopyranoside (pNPG) and cellobiose catalysis. [ABSTRACT FROM AUTHOR]

Abstract The Pseudomonas sp. have been long recognized for their exogenous lipolytic activities yet the genus still contains a lot of unexplored strains. Due to the versatile metabolic machinery and their potential for adaptation to fluctuating environmental conditions Pseudomonas sp. are of great interest for biotechnological applications. In this study, a new extracellularly produced lipolytic enzyme from Pseudomonas sp. (P. reinekei) was purified and characterized. The production of lipase from P. reinekei (H1) was enhanced 10-fold by optimizing the nitrogen source. The 50 kDa H1 lipase was purified using negative and positive mode anion exchange chromatography. The purified lipase was active over a broad pH range (5.0–9.0) and was stable for 24 h at 40 °C. The lipase showed significant stability, and indeed activation, in the presence of organic solvents with log P ≥ 2.0. These features render this lipase of interest as a biocatalyst for applications such as biodiesel production, detergent formulations and biodegradation of oil in the environment. Highlights • A novel lipase, from an under researched sub-species, has been isolated and fully characterised. • Production of this extracellular lipase was enhanced 10-fold through media engineering. • An innovative, two-stage anion exchange purification strategy was developed and optimised. • The novel lipase displays excellent organo-stability, and organo-activation, in the presence of organic solvents with log P ≥ 2.0. • This new lipase offers many biotechnological opportunities in non-aqueous biotransformations, detergent formulations and biodegradation of environmental waste oil. [ABSTRACT FROM AUTHOR]

The production of high yields of soluble recombinant protein is one of the main objectives of protein biotechnology. Several factors, such as expression system, vector, host, media composition and induction conditions can influence recombinant protein yield. Identifying the most important factors for optimum protein expression may involve significant investment of time and considerable cost. To address this problem, statistical models such as Design of Experiments (DoE) have been used to optimise recombinant protein production. This reviewexamines the application ofDoE in the production of recombinant proteins in prokaryotic expression systems with specific emphasis onmedia composition and culture conditions. The review examines the most commonly used DoE screening and optimisation designs. It provides examples of DoE applied to optimisation of media and culture conditions. [ABSTRACT FROM AUTHOR]

Abstract: Toxic aldehydes produced by alcohol dehydrogenases have been implicated in the pathogenesis of Helicobacter pylori-related damage to the gastric mucosa. Despite this, the enzymes that might be responsible for producing such aldehydes have not been fully described. It was, therefore, of considerable interest to characterize the alcohol oxidizing enzymes in this pathogen. Previous work in this laboratory characterized two such H. pylori enzymes that had broad specificity for a range of aromatic alcohol substrates. However, an enzyme with specificity for aliphatic alcohols is likely to be required in order that H. pylori can metabolize the wide range of substrates encountered in the gastric mucosa. In this study we describe HpSCADH, an alcohol dehydrogenase from H. pylori 26695 with broad specificity for aliphatic alcohols. HpSCADH was classified in the cD1e subfamily of classical short chain alcohol dehydrogenases. The enzyme was a monomer of approximately 29kDa with a preference for NAD+ as cofactor. Pyrazole was found to be a competitive inhibitor of HpSCADH. The physiological role of this enzyme was explored by construction of an HpSCADH isogenic mutant. At pH 7.0 the mutant showed reduced growth which became more pronounced when the pH was lowered to 5.0. When pyrazole was added to wild type H. pylori cells it caused growth profiles to be reduced to match those of the isogenic mutant suggesting that HpSCADH inhibition alone was responsible for growth impairment. Taken together, the data relating to the alcohol metabolizing enzymes of this pathogen indicate that they play an important role in H. pylori growth and adaptation to acidic environments. The therapeutic potential of targeting H. pylori alcohol dehydrogenases is discussed. [Copyright &y& Elsevier]

Caffeine is a plant alkaloid present in food and beverages consumed worldwide. It has high lipid solubility with recognized actions in the central nervous system and in peripheral tissues, notably the adipose depots. However, the literature is scant regarding caffeine's influence on adipocyte functions other than lipolysis, such as glucose incorporation into lipids (lipogenesis) and amine oxidation. The objective of this study was to explore the direct effects of caffeine and of isobutylmethylxanthine (IBMX) on these adipocyte functions. Glucose transport into fat cells freshly isolated from mice, rats, or humans was monitored by determining [3H]-2-deoxyglucose (2-DG) uptake, while the incorporation of radiolabeled glucose into cell lipids was used as an index of lipogenic activity. Oxidation of benzylamine by primary amine oxidase (PrAO) was inhibited by increasing doses of caffeine in human adipose tissue preparations with an inhibition constant (Ki) in the millimolar range. Caffeine inhibited basal and insulin-stimulated glucose transport as well as lipogenesis in rodent adipose cells. The antilipogenic action of caffeine was also observed in adipocytes from mice genetically invalidated for PrAO activity, indicating that PrAO activity was not required for lipogenesis inhibition. These caffeine inhibitory properties were extended to human adipocytes: relative to basal 2-DG uptake, set at 1.0 ± 0.2 for 6 individuals, 0.1 mM caffeine tended to reduce uptake to 0.83 ± 0.08. Insulin increased uptake by 3.86 ± 1.11 fold when tested alone at 100 nM, and by 3.21 ± 0.80 when combined with caffeine. Our results reinforce the recommendation of caffeine's potential in the treatment or prevention of obesity complications. [ABSTRACT FROM AUTHOR]

Methylxanthines are among the most widely consumed drugs in the world and evidence of their health benefits has been growing in recent years. Primary Amine Oxidase (PrAO) has been recognized as a therapeutic target for the amelioration of inflammatory, vascular, and neurodegenerative diseases. Previous work in our laboratories showed that caffeine inhibited Bovine PrAO with a Ki of 1.0 mM using benzylamine as substrate. This study aimed to extend our previous work and explore the possibility that related methylxanthines might influence PrAO activity. While paraxanthine, theophylline, and 7‐methylxanthine had little effect on PrAO, theobromine was a noncompetitive inhibitor with a Ki of 276 ± 44 µM. The specific structural elements of methylxanthines that are required for inhibition allow us to suggest that their binding site on PrAO may be a target for therapeutics. The health benefits associated with dietary methylxanthine consumption could involve PrAO inhibition. Practical applications: Inhibition of PrAO by methylxanthines may be significant in conferring health benefits. The design of PrAO inhibitors based on the structural motifs identified in this study (N‐methylation at specific locations) is indicated. Existing therapeutics based on a core xanthine structure can be evaluated for their effects on PrAO. PrAO inhibition must be considered as a potential mediator of the beneficial health effects of some methylxanthines. If inhibition in human tissues is comparable to, or greater than, that found in these studies it points to an important role for these compounds in human health. Theobromine, like caffeine, is a noncompetitive inhibitor of Primary Amine Oxidase (PrAO). Xanthine methylation at positions 3 and 7 is required for inhibition of PrAO. The methylxanthine binding site on PrAO may be a target for therapeutics. [ABSTRACT FROM AUTHOR]