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Natural products and analogues are a source of antibacterial drug discovery. Considering drug resistance levels emerging for antibiotics, identification of bacterial metalloenzymes and the synthesis of selective inhibitors are interesting for antibacterial agent development. Peptide nucleic acids are attractive antisense and antigene agents representing a novel strategy to target pathogens due to their unique mechanism of action. Antisense inhibition and development of antisense peptide nucleic acids is a new approach to antibacterial agents. Due to the increased resistance of biofilms to antibiotics, alternative therapeutic options are necessary. To develop antimicrobial strategies, optimisedinvitroandinvivomodels are needed. In vivo models to study biofilm-related respiratory infections, device-related infections: ventilator-associated pneumonia, tissue-related infections: chronic infection models based on alginate or agar beads, methods to battle biofilm-related infections are discussed. Drug delivery in case of antibacterials often is a serious issue therefore this review includes overview of drug delivery

Enzymatic inhibition of histone deacetylase (HDAC) activity is emerging as an innovative and effective approach for the treatment of cancer. A series of novel amide derivatives have been synthesized and evaluated for their ability to inhibit human HDACs. Multiple compounds were identified as potent HDAC inhibitors (HDACi), with IC50 values in the low nanomolar (nM) range against enzyme activity in HeLa cell extracts and sub-μM for their in vitro anti-proliferative effect on cell lines. The introduction of an unsaturated linking group between the terminal aryl ring and the amide moiety was the key to obtain good potency. This approach yielded compounds such as (E)-N-[6-(hydroxyamino)-6-oxohexyl]-3-(7-quinolinyl)-2-propenamide (27) (HDAC IC50 8 nM) which showed potent in vivo activity in the P388 mouse leukemia syngeneic model (an increased lifespan (ILS) of 111% was obtained).

Malignant cells display increased demands for energy production and DNA repair. Nicotinamide adenine dinucleotide (NAD) is required for both processes and is also continuously degraded by cellular enzymes. Nicotinamide phosphoribosyltransferase (Nampt) is a crucial factor in the resynthesis of NAD, and thus in cancer cell survival. Here, we establish the cytotoxic mechanism of action of the small molecule inhibitor CHS-828 to result from impaired synthesis of NAD. Initially, we detected cross-resistance in cells between CHS-828 and a known inhibitor of Nampt, FK866, a compound of a structurally different class. We then showed that nicotinamide protects against CHS-828-mediated cytotoxicity. Finally, we observed that treatment with CHS-828 depletes cellular NAD levels in sensitive cancer cells. In conclusion, these results strongly suggest that, like FK866, CHS-828 kills cancer cells by depleting NAD.

High-resolution crystallographic structures of recombinant human peroxisome proliferator-activated receptor ligand-binding domain (isotype beta/delta) reveal a fatty acid in the binding site. Mass spectrometry confirmed the presence of C16:0, C16:1, C18:0 and C18:1 in a ratio of approximately 3:2:1:4 with 11, Z-octadecenoic acid (cis-vaccenic acid) identified as the predominant species. These are endogenous fatty acids acquired from the bacterial expression system, and serve to lock the ligand-binding domain into the activated conformation. A requirement for crystal growth, the additive n-heptyl-beta-d-glucopyranoside, binds near the activation function helix where recognition of co-activator proteins occurs. Our observations suggest potential physiological ligands for human PPAR-beta/delta and highlight that reported binding studies must be treated with caution unless endogenous fatty acids have been removed from the sample prior to analysis.

The cyanoguanidine CHS 828 has shown promising antitumor properties and is currently in early clinical trials, although the mechanism of action still is largely unknown. In this study, resistant sublines of the histiocytic lymphoma cell line U-937 GTB and the myeloma line RPMI 8226 were developed by culturing under gradually increasing concentrations of CHS 828 until reaching 25 times the parental line EC50s. The new phenotypes demonstrate more than 400-fold resistance to CHS 828 and cross-resistance to six cyanoguanidine analogs, but no resistance to nine standard drugs of different mechanistic classes or to the cytotoxic guanidines m-iodobenzylguanidine and methylglyoxal-bis(guanylhydrazone). The resistant phenotypes were stable for several months even if cultivated in drug-free medium and no difference in proliferation, ultrastructural or morphologic appearance in the sublines could be detected. Neither was decreased accumulation of tritium-labeled CHS 828 observed. Furthermore, the new U-937 phenotype was not accompanied by changes in differentiation or an altered cell-cycle distribution. In the myeloma cell line, esterase activity was shown to be moderately enhanced. Two-dimensional protein electrophoresis was undertaken to unmask possible resistance-mediating proteins and/or the target molecule(s) for CHS 828. In the myeloma cell line, lambda light chain immunoglobulin (down-regulated) and a fatty acid-binding protein (up-regulated) were identified. The findings presented here indicate that development of specific cellular alterations is responsible for the gained CHS 828 resistance.

Hapten derivatives of 1α,25-dihydroxyvitamin D3 and its 20-epimer were synthesized and conjugated to a carrier protein for raising polyclonal antibodies. The haptens were linked through spacers at C-16, thereby exposing both the A-ring and the side chain of the molecules, to maximize antibody specificity. The spacers were introduced via stereoselective hydroboration of 16-ene intermediates as the key step. In immunoassays, the antibodies raised toward the natural hormone were selective to this compound over derivatives with modifications in the A-ring or the side chain. The antibodies toward the 20-epimer, however, were unable to recognize modifications in the side chain.

The nutritional value of glycerol-1,2,3-tris(methylsuccinate), a novel ester of succinic acid with high insulinotropic efficiency both in vitro and in vivo, was assessed in both fed and starved rats. The infusion of the ester, given in a daily amount (1.2 micromol. g body wt-1) well in excess of what could result from its repeated intravenous administration as an insulinotropic agent in non-insulin-dependent diabetes (0.07 micromol. g body wt-1 for each administration), failed to prevent the fall in body weight, liver and muscle glycogen contents, and plasma d-glucose or insulin concentration, as well as the increase in plasma free fatty acid and beta-hydroxybutyrate concentrations caused by starvation. The sole indications that the ester may serve, to a limited extent, as an alternative nutrient in starved rats consisted in a somewhat higher weight of both liver and paraovarian adipose tissue and somewhat higher activity of liver glucokinase in rats receiving the ester than in animals infused with saline. The low nutritional value of this ester thus answers the objection of its possible role as an extrapancreatic nutrient or gluconeogenic precursor in the perspective of its use as an insulinotropic tool in type 2 diabetes.

The nuclear hormone 1a,25-dihydroxyvitamin D3 (VD) has important cell-regulatory functions but also a strong calcemic effect. Therefore, various VD analogues have been synthesized and screened for their biological profile. In order to gain more insight into the molecular basis of the high antiproliferative but low calcemic action of the VD analogue EB1089, we characterized this compound in comparison to five structurally related VD analogues. The activities of the six VD analogues in in vitro assays (limited protease digestion assays for determining interaction with monomeric vitamin D receptor (VDR), ligand-dependent gel shift assays for showing the increase of DNA binding of VDR-retinoid X receptor (RXR) heterodimers, and reporter gene assays on different types of VD response elements for demonstrating the efficacy in nuclear VD signalling) were found to represent their biological potency (antiproliferative effect on different malignant cell lines). In this series, EB1089 proved to be the most potent VD analogue; that is, every structural modification (20-epi configuration, cis-configuration at position C24, or changes at the ethyl groups at position C25) appeared to reduce the determined activities mediated through the VDR of these analogues. Moreover, the modifications of EB1089 resulted in a loss of VD response element selectivity, suggesting that this parameter is very critical for the biological profile of this VD analogue. J. Cell. Biochem. 71:340-350, 1998. r 1998 Wiley-Liss, Inc.

Selected esters of succinic acid are currently under investigation as possible insulinotropic agents for the treatment of noninsulin-dependent diabetes mellitus. The aim of the present study was to investigate the effects of ten novel esters of succinic acid upon biosynthetic activity in rat pancreatic islets. In the absence of any other exogenous nutrient, glycerol-3-hydroxy-1,2-dimethyl succinate (0.5 mM), D-arabitol-5-hydroxy-1,2,3,4-tetramethylsuccinate (0.5 mM), and 4-tert-butylsuccinate (2.5 mM) exerted little or no effect upon L-[4-3H]phenylalanine incorporation into trichloroacetic acid-precipitable material. A modest but significant increase in biosynthetic activity to approximately 150% of basal value was found in the presence of L-threitol-1,2,4-trimethylsuccinate (2.0 mM) and ethanediol-1,2-diethylsuccinate (2.5 mM). A two- to five-fold increase in protein biosynthesis was observed in islets exposed to propanediol-1,2-dimethylsuccinate, glycerol-1,2-dimethylsuccinate-3-hydrogenosuccinate, L-threitol-3-succinoyl-1,2,4-trimethylsuccinate, glycerol-1,2-dimethylsuccinate or ethanediol-1,2-dimethylsuccinate (2.5 mM each), these esters being mentioned in order of increasing biological efficiency. There was a significant correlation between these results and the insulinotropic action of the same esters. The present findings thus reinforce the view that such esters act as nutrients in islet cells and, therefore, offer the advantage over pharmacological agents currently used for the treatment of type-2 diabetes in stimulating both the biosynthetic and secretory activity of insulin-producing B-cells.

Selected esters of succinic acid are currently under investigation as insulinotropic tools for the treatment of non-insulin-dependent diabetes mellitus. The aim of the present study was to investigate, in isolated rat pancreatic islets, the insulin secretory response to ten novel esters of succinic acid. According to six different methods of comparison, the following hierarchy in insulinotropic potential was established: 4-tert-butyl-succinateor = glycerol-1,2-dimethylsuccinate-3-hydrogenosuccinateor = threitol-3-succinoyl-1,2,4-trimethylsuccinateor = ethanediol-1,2-diethylsuccinateor = glycerol-1,2-dimethylsuccinateor = glycerol-3-hydroxy-1,2-dimethylsuccinateor = arabitol-5-hydroxy-1,2,3,4-tetramethylsuccinateor = threitol-1,2,4-trimethylsuccinateor = ethanediol-1,2-dimethylsuccinatepropanediol-1,2-dimethylsuccinate. There was a close correlation (r = 0.823) between the insulinotropic potential and the minimal effective concentration, which ranged between the extreme values of 10 microM and 2.5 mM. In the presence of the esters, the concentration-response relationship for glucose-stimulated insulin release was changed from its typically sigmoidal shape to a hyperbolic pattern, with most agents enhancing insulin output at a low hexose concentration (2.8 mM) but failing to do so at a high glucose level (16.7 mM). Highly potent insulinotropic esters have several advantages over other antidiabetic agents in clinical use.

Introduction APO866 is a new anti-tumor compound inhibiting nicotinamide phosphoribosyltransferase (NAMPT). APO866 has an anti-tumor effect in several pre-clinical tumor models and is currently in several clinical phase II studies. 3′-deoxy-3′-[18F]fluorothymidine ([18F]FLT) is a tracer used to assess cell proliferation in vivo. The aim of this study was non-invasively to study effect of APO866 treatment on [18F]FLT and 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) uptake. Methods In vivo uptake of [18F]FLT and [18F]FDG in human ovary cancer xenografts in mice (A2780) was studied at various time points after APO866 treatment. Baseline [18F]FLT or [18F]FDG scans were made before treatment and repeated after 24 hours, 48 hours and 7 days. Tumor volume was followed with computed tomography (CT). Tracer uptake was quantified using small animal PET/CT. One hour after iv injection of tracer, static PET scans were performed. Imaging results were compared with Ki67 immunohistochemistry. Results Tumors treated with APO866 had volumes that were 114% (24 h), 128% (48 h) and 130% (Day 7) relative to baseline volumes at Day 0. In the control group tumor volumes were 118% (24 h), 145% (48 h) and 339% (Day 7) relative to baseline volumes Day 0. Tumor volume between the treatment and control group was significantly different at Day 7 (P = 0.001). Compared to baseline, [18F]FLT SUVmax was significantly different at 24 h (P

Introduction: A combination of carboplatin and paclitaxel is often used as first line chemotherapy for treatment of ovarian cancer. Therefore the use of imaging biomarkers early after initiation of treatment to determine treatment sensitivity would be valuable in order to identify responders from non-responders. In this study we describe the noninvasive PET imaging of glucose uptake and cell proliferation using 2-deoxy-2-[ 18 F]fluoro-D-glucose (FDG) and 3’deoxy-3’-[ 18 F]fluorothymidine (FLT) for early assessment of treatment response in a pre-clinical mouse model of human ovarian cancer treated with carboplatin and paclitaxel. Methods: In vivo uptake of FLT and FDG in human ovarian cancer xenografts in mice (A2780) was determined before treatment with carboplatin and paclitaxel (CaP) and repeatedday 1, 4 and 8 after treatment start. Tracer uptake was quantified using small animal PET/CT. Tracer uptake was compared with gene expression of Ki67, TK1, GLUT1, HK1 and HK2. Results: Tumors in the CaP group was significantly smaller than in the control group (p=0.03) on day 8. On day 4 FDG SUVmax ratio was significantly lower in the CaP group compared to the control group (105±4% vs 138±9%; p=0.002) and on day 8 the FDG SUVmax ratio was lower in the CaP compared to the control group (125±13% vs 167±13%; p=0.05). On day 1 the uptake of FLT SUVmax ratio was 89±9% in the CaP group and 109±6% in the control group; however the difference was not statistically significant (p=0.08). Conclusions: Our data suggest that both FDG and FLT PET may be used for the assessment of anti-tumor effects of a combination of carboplatin and paclitaxel in the treatment of ovarian cancer. FLT provides an early and transient signal and FDG a later and more prolonged response. This underscores the importance of optimal timing between treatment and FLT or FDG imaging since treatment response may otherwise be overlooked.

AIM: 3'-deoxy-3'-[¹⁸F]fluorothymidine ([18F]FLT) is a tracer used to assess cell proliferation in vivo. The aim of the study was to use [18F]FLT positron emission tomography (PET) to study non-invasively early anti-proliferative effects of the experimental chemotherapeutic agent TP202377 in both sensitive and resistant tumors. METHODS: Xenografts in mice from 3 human cancer cell lines were used: the TP202377 sensitive A2780 ovary cancer cell line (n = 8-16 tumors/group), the induced resistant A2780/Top216 cell line (n = 8-12 tumors/group) and the natural resistant SW620 colon cancer cell line (n = 10 tumors/group). In vivo uptake of [18F]FLT was studied at baseline and repeated 6 hours, Day 1, and Day 6 after TP202377 treatment (40 mg/kg i.v.) was initiated. Tracer uptake was quantified using small animal PET/CT. RESULTS: TP202377 (40 mg/kg at 0 hours) caused growth inhibition at Day 6 in the sensitive A2780 tumor model compared to the control group (P

In the lipase-catalyzed double enantioselective transesterification between the meso-diol 1 and the racemic 2,2,2-trifluoroethyl 2-chloropropanoate (rac-2) by the immobilized lipase preparation SP 382 from Candida antarctica, consisting of the components A and B, component B only is responsible for the enantioselectivity.

Lipase catalyzed synthesis of long chain peroxycarboxylic acids from hydrogen peroxide and free carboxylic acid was investigated. A 51% yield of peroxytetradecanoic acid was achieved when using a two phase system of toluene and water. The peroxy acids thus formed were applied for in situ oxidation of alkenes, in general leading to high yields of the corresponding epoxide. For example, a quantitative yield of cyclohexene oxide and a 94% yield of 1-hexadecene oxide was achieved in a solvent-free process.

The fatty acid specificity of the B-lipase derived from Candida antarctica was investigated in the synthesis of esters of ethyl D-glucopyranoside. The specificity was almost identical with respect to straight-chain fatty acids with 10 to 18 carbon atoms. However, lower fatty acids such as hexanoic and octanoic acid and the unsaturated 9-cis-octadecenoic acid were found to be poor substrates of the enzyme. As a consequence of this selectivity, these fatty acids were accumulated in the unconverted fraction when ethyl D-glucopyranoside was esterified with an excess of a mixture of fatty acids. This accumulation can reduce the overall effectiveness of the process as the activity of the lipase was found to be reduced when exposed to high concentrations of short-chain fatty acids. Finally, using a simplified experimental set-up, the specificity of the C. antarctica B-lipase was compared to the specificity of lipases derived from C. rugosa, Mucor miehei, Humicola, and Pseudomonas. Apart from the C. rugosa lipase...

LIPASES are hydrolytic enzymes which break down triacylglycerides into free fatty acids and glycerols. They have been classified as serine hydrolases owing to their inhibition by diethyl p-nitrophenyl phosphate1. Lipase activity is greatly increased at the lipid-water interface2,3, a phenomenon known as interfacial activation. X-ray analysis has revealed the atomic structures of two triacylglycerol lipases, unrelated in sequence: the human pancreatic lipase (hPL)4, and an enzyme isolated from the fungus Rhizomucor (formerly Mucor) miehei5 (RmL). In both enzymes the active centres contain structurally analogous Asp-His-Ser triads (characteristic of serine proteinases), which are buried completely beneath a short helical segment, or 'lid'. Here we present the crystal structure (at 3 A resolution) of a complex of R. miehei lipase with n-hexylphosphonate ethyl ester in which the enzyme's active site is exposed by the movement of the helical lid. This movement also increases the nonpolarity of the surface surrounding the catalytic site. We propose that the structure of the enzyme in this complex is equivalent to the activated state generated by the oil–water interface.

Recognition of the advantages of the use of lipases relative to traditional chemical processes indicates that lipases may be expected to gain in importance in the enzyme market. Development of lipase technologies for the synthesis of novel compounds will probably also result in their expansion into new areas, and a major impact on a range of industries.

Anthracycline-induced cardiomyopathy is a major problem in anti-cancer therapy. The only approved agent for alleviating this serious dose limiting side effect is ICRF-187 (dexrazoxane). The current thinking is that the ring-opened hydrolysis product of this agent, ADR-925, which is formed inside cardiomyocytes, removes iron from its complexes with anthracyclines, hereby reducing the concentration of highly toxic iron-anthracycline complexes that damage cardiomyocytes by semiquinone redox recycling and the production of free radicals. However, the 2 carbon linker ICRF-187 is also is a catalytic inhibitor of topoisomerase II, resulting in the risk of additional myelosuppression in patients receiving ICRF-187 as a cardioprotectant in combination with doxorubicin. The development of a topoisomerase II-inactive iron chelating compound thus appeared attractive. In the present paper we evaluate the topoisomerase II-inactive 3 carbon linker bisdioxopiperazine analog ICRF-161 as a cardioprotectant. We demonstrate that this compound does chelate iron and protects against doxorubicin-induced LDH release from primary rat cardiomyocytes in vitro, similarly to ICRF-187. The compound does not target topoisomerase II in vitro or in cells, it is well tolerated and shows similar exposure to ICRF-187 in rodents, and it does not induce myelosuppression when given at high doses to mice as opposed to ICRF-187. However, when tested in a model of chronic anthracycline-induced cardiomyopathy in spontaneously hypertensive rats, ICRF-161 was not capable of protecting against the cardiotoxic effects of doxorubicin. Modulation of the activity of the beta isoform of the topoisomerase II enzyme by ICRF-187 has recently been proposed as the mechanism behind its cardioprotection. This concept is thus supported by the present study in that iron chelation alone does not appear to be sufficient for protection against anthracycline-induced cardiomyopathy.

BACKGROUND: Selected esters of succinic acid were recently proposed as novel nutrients to support ATP generation in cells endangered by an imbalance between the formation and breakdown of this adenine nucleotide. In the present study, a new ester, glycerol-1,2,3-trimethylsuccinate, was examined for its potential beneficial effect in the procedures preceding liver transplantation. METHODS: The viability and metabolic behavior of hepatocytes were examined after perfusion and storage of rat livers for 20 hr at 4 degrees C with a Belzer UW-CSS solution in the absence or presence or 2 mM glycerol-1,2,3-trimethylsuccinate. RESULTS: Although it failed to affect significantly the release of cellular enzymes during storage and the protein or glycogen content of the liver, and was unable to prevent the storage-induced decrease in both biosynthetic activity and D-[U-14C]glucose incorporation into glycogen in isolated hepatocytes, the ester restored to a close-to-normal value the viability of the hepatocytes and opposed the starvation-like effects of liver storage upon both the conversion of D-[U-14C]glucose to 14CO2 and radioactive amino acids and the de novo generation of 14C-labeled D-glucose from [2-14C]pyruvate. CONCLUSIONS: Because succinic acid esters are efficiently metabolized in several cell types, the present results suggest that such esters may have a wide field of application in transplantation procedures.

We wish to report the synthesis and structure-activity relationship (SAR) of a series of 4-aminobenzophenones, as a novel compound class with high antiinflammatory activity. Our initial lead, (4-[(2-aminophenyl)amino]phenyl)(phenyl)methanone (3), was systematically optimized and resulted in compounds that potently inhibited the release of the proinflammatory cytokines IL-1beta and TNF-alpha in human peripheral blood mononuclear cells stimulated by LPS. One of the most potent compounds, among others, was (4-[(2-aminophenyl)amino]-2-chlorophenyl)(2-methylphenyl)methanone (45) with IC(50) values of 14 and 6 nM for the inhibition of IL-1beta and TNF-alpha, respectively. Furthermore, we found these types of compounds to be potent and selective p38 MAP kinase inhibitors, e.g. 45 had an IC(50) value of 10 nM. Molecular modeling was used to rationalize our SAR data and to propose a model for the interaction of compound 45 with the p38 MAP kinase. The model involved a favorable hydrogen bond between the carbonyl group of the benzophenone and the NH of Met-109, positioning ring A in the hydrophobic pocket I of the enzyme. Good antiinflammatory effects were demonstrated in two murine models of dermatitis after topical application (oxazolone and TPA model).

A hapten derivative of EB1089 [1(R),3(S),25-trihydroxy-26,27-dimethyl-9,10-seco-24-homocholesta-5(Z),7(E),10(19),22(E),24(E)-pentaene], a side-chain analog of 1α,25-dihydroxyvitamin D 3 , was synthesized for raising antibodies with a high specificity for EB1089. The A-ring moiety of EB1089 was replaced in the hapten by a linker for conjugation to a protein. Three polyclonal antibodies were obtained by immunizing rabbits with a BSA-conjugate of the hapten. The antibodies were characterized for titer, avidity and specificity using an enzyme immunoassay with covalently bound EB1089. The three antibodies had similar binding profiles and were highly selective for EB1089 and its metabolites over the naturally occurring vitamin D metabolites. Cross-reactivities with 25-hydroxyvitamin D 3 , the most abundant vitamin D metabolite in serum, were in the range 0.01–0.2% relative to EB1089.

CHS 828, a newly recognized pyridyl cyanoguanidine, has shown promising antitumor activity both in vitro and in vivo and is presently in early phase I clinical trial in collaboration with EORTC. In this study, the effects of CHS 828 and a series of analogues on extracellular acidification and cytotoxicity were compared with those of m -iodobenzylguanidine (MIBG) in human tumor cells. The extracellular acidification rate was measured using the Cytosensor microphysiometer, and determination of cytotoxicity and proliferation was [ 14 C] performed by the fluorometric microculture cytotoxicity assay (FMCA) and measurement of [ 14 C]thymidine and leucine uptake. CHS 828 significantly increased the acidification rate during the first 15–24 hr in a concentration-dependent manner. This effect was abolished by removal of glucose from the medium, substituted with 10 mM of pyruvate, indicating stimulated glycolysis as the source of the increased acidification rate. However, CHS 828 induced cytotoxicity at concentrations well below those that affected the rate of acidification; when a series of closely related pyridylguanidine analogues were tested and compared, no apparent relationship between cytotoxicity and acidification could be discerned. Furthermore, comparable increases in the acidification rate were evident in one subline with high-grade resistance to the cytotoxic actions of CHS 828. The results indicate that CHS 828 may share the inhibitory actions of MIBG on mitochondrial respiration with a subsequent increase in glycolysis and acidification rate. However, this mechanism of action appears neither necessary nor sufficient to fully explain the cytotoxic actions of CHS 828 in human tumor cells, actions which remain to be mechanistically clarified.

The metabolism of [1,3-(13)C]glycerol-1,2,3-tris(methylsuccinate) and glycerol-1,2,3-tris(methyl[2,3-(13)C] succinate) was examined in hepatocytes prepared from hereditarily diabetic Goto-Kakizaki rats. Over 120 min incubation in the presence of one of the two (13)C-labelled esters (2.5 mM), the output of (13)C-enriched glucose averaged 57.1 +/- 18.5 and 54.1 +/- 22.7 nmol per 10(6) cells, when expressed as [1,3-(13)C]glycerol and [2,3-(13)C] succinate equivalent, respectively. In the case of [1,3-(13)C]glycerol-1,2,3-tris(methyl-succinate), the molecules of glucose were symmetrically labelled. In the case of glycerol-1,2,3-tris(methyl[2,3-(13)C] succinate), however, both the single-labelled and double-labelled isotopomers of glucose contained more (13)C atoms in their C(6)-C(5)-C(4) than C(1)-C(2)-C(3) moiety. These findings indicate that glycerol-1,2,3-tris(methylsuccinate), recently proposed as a novel insulinotropic tool for the treatment of non-insulin-dependent diabetes mellitus, is efficiently metabolized in hepatocytes from diabetic rats, the high rate of gluconeogenesis coinciding with channelling of D-glyceraldehyde-3-phosphate between glyceraldehyde-3-phosphate dehydrogenase and phosphofructoaldolase.

Epoxidation of alkenes was achieved under extremely mild conditions by employing peroxycarboxylic acids formed continuously in situ by lipase-catalysed perhydrolysis of the corresponding carboxylic acids.

Peroxisome proliferator-activated receptors (PPARs), a subgroup of the nuclear hormone receptor family, adopt an activated configuration in the presence of an agonist (Nolte et al., 1998) and bind the retinoid X receptor (RXR) and additional coactivator proteins to create a complex capable of interacting with specific DNA response elements. The target genes regulated by PPARs modulate lipid metabolism and/or glucose homeostasis together with energy expenditure (Willson et al., 2000).

The metabolism of14C-labelled glycerol-1,2,3-trimethylsuccinate (2.0 mM) was examined in rat pancreatic islets. The oxidation of the glycerol moiety of the ester was negligible relative to that of its succinate residues. The oxidation of glycerol-1,2,3-trimethyl[1,4-14C]succinate was two times higher than that of glycerol-1,2,3-trimethyl[2,3-14C]succinate, this difference being matched by a higher generation of14C-labelled acidic metabolites and amino acids from the latter than from the former tracer. The total generation of14CO2from the ester, uniformly labelled except in its methyl groups, was close to that found for the oxidation of 1.0 mM D-[U-14C]glucose. These findings thus reveal that glycerol-1,2,3-trimethylsuccinate is efficiently metabolized in islet cells and support the idea that this ester could be used as a nutrient to bypass defects of D-glucose transport and metabolism in the islet B-cell and, hence, improve proinsulin biosynthesis and insulin release in non-insulin-dependent diabetes mellitus.

Ethyl hexylchlorophosphonate and analogues thereof were investigated as inhibitors of lipases. Both microbial and mammalian lipases were irreversibly inhibited. The inhibition could be monitored by p -nitrophenol release from the corresponding ethyl p -nitrophenyl hexylphosphonate inhibitor. Quantitative analysis of the data indicated that a 1:1 lipase-inhibitor complex was formed during inhibition. Enantioselective inhibition was found for the lipases derived from Candida antarctica and Rhizomucor miehei using pure enantiomers of ethyl p -nitrophenyl hexylphosphonate as inhibitors. Using the same inhibitor, reversed enantioselectivity was found for the protease α-chymotrypsin as compared to the two lipases.

Graphical abstract, A number of hydroxamic acid derivatives which inhibit human histone deacetylases were investigated for efficacy against cultured bloodstream form Trypanosoma brucei. Three out of the four classes tested displayed significant activity. The majority of compounds blocked parasite growth in the submicromolar range. The most potent was a member of the sulphonepiperazine series with an IC50 of 34 nM. These results identify lead compounds with potential for the development of a novel class of trypanocidal agent.

Humicola lanuginosa lipase was used for enantioselective hydrolyses of a series of homologous 2-phenoxyalkanoic acid ethyl esters. The enantioselectivity (E-value) of the enzyme changed from an (R) ...