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The enzymatic transfer of phosphoryl groups is central to the control of many cellular processes. One of the phosphoryl transfer mechanisms, that of acetate kinase, is not completely understood. Besides better understanding of the mechanism of acetate kinase, knowledge of the structure of butyrate kinase 2 (Buk2) will aid in the interpretation of active-site structure and provide information on the structural basis of substrate specificity. The gene buk2 from Thermotoga maritima encodes a member of the ASKHA (acetate and sugar kinases/heat shock cognate/actin) superfamily of phosphotransferases. The encoded protein Buk2 catalyzes the phosphorylation of butyrate and isobutyrate. We have determined the 2.5-[Angstrom] crystal structure of Buk2 complexed with ([beta],[gamma]-methylene) adenosine 5'-triphosphate. Buk2 folds like an open-shelled clam, with each of the two domains representing one of the two shells. In the open active-site cleft between the N- and C-terminal domains, the active-site residues consist of two histidines, two arginines, and a cluster of hydrophobic residues. The ATP binding region of Buk2 in the C-terminal domain consists of abundant glycines for nucleotide binding, and the ATP binding motif is similar to those of other members of the ASKHA superfamily. The enzyme exists as an octamer, in which four disulfide bonds form between intermolecular cysteines. Sequence alignment and structure superposition identify the simplicity of the monomeric Buk2 structure, a probable substrate binding site, the key residues in catalyzing phosphoryl transfer, and the substrate specificity differences among Buk2, acetate, and propionate kinases. The possible enzyme mechanisms are discussed.

Investigate on the computational evidence against the mechanism of alpha-hydroxycarbonyl formation is done. In the conclusion the master equation simulations are necessary to quantify the extent to which carboxylic acids from anti carbonyl oxides also contributes to HO(sub x) production in ozonolysis.

Crystal structure analyses reveal that acetate kinase contains a core fold identical to the ADP-binding domains of ASKHA superfamily of phosphotransferases and an epsilon conformation of a residue that binds the alpha-phosphate of ADP. However, acetate kinase differs from ASKHA in possessing numerous charged active-site residues.

Research reveals that benzoylformate decarboxylase reaction with p-nitrobenzoylformic acid shows two transient states of the enzyme-substrate complex yielding a chromophoric product exhibiting absorbance in the visible spectrum. Analysis of the variant enzyme's His70Ala active-site, indicates the role of histidine70 in the decarboxylation pathway of the enzyme.

Research is done on the OH radical which is the key oxidizing agent in the troposphere, and ozone--alkene reactions appear to be a significant and sometimes dominant source of new HO, radicals in urban and rural air. In conclusion, they lead to the proposal that the formation of a hydroperoxide via a diradical pathway can compete with the formation of the carbonyl oxide for the ethene primary ozonide.

The authors discuss OH formation yields for a series of terminal alkenes reacting with ozone. Results demonstrate the relationship between the terminal alkene structure and OH formation.

The crystal structure of the thiamin diphosphate (ThDP)-dependent enzyme benzoylformate decarboxylase (BFD) was determined at 1.6 angstrom resolution. BFD when compared to other ThDP-dependent enzymes displayed similar architecture to the enzymes. While the cofactor- and metal-binding sites were well conserved, the active site residues not directly bound to the cofactor were not. However, it was also observed that the position of functional groups in the functional sites may be well conserved.

A superfamily of enzymes related by their ability to catalyze the abstraction of the alpha-proton of a carboxylic acid to produce an enolic intermediate has been identified. The established and deduced structure-function relationships in the superfamily enable the prediction that other apparent members of the family for which no catalytic functions have yet been assigned will also catalyze the abstraction of the alpha-protons of carboxylic acids.

The process of wound healing is highly complex, and any changes of the key healing factors or components can produce undesirable outcomes. Current clinical practices such as off-loading, debridement, irrigation, suturing, negative therapy of pressure, grafting and the supplementation of growth factors and so on, have limits in addressing the problems of comprehensive wound care. Due to the dynamic nature of the healing process, the best prevention strategies possible are effective wound management in the early stages and preventing the development of wounds to chronic conditions. The immune system has been shown to play a vital role in the physiological process of wound healing and tissue repair. Many agents that affect the immune system positively, both synthetic and natural, were shown to have implications for wound healing process. In particular, bioactive materials have shown promising consequences in this area, as a result of advances in inter-disciplinary approaches that can potentially be used as a smart wound care. Natural polysaccharides, with their clearly elucidated structures, identified cellular activities and desirable physical properties have the potential to work as therapeutic tools for tissue regeneration and wound healing. In this review article we discuss briefly the essential role of the immune system and emergence of natural wound healing polysaccharide applications. First, we introduce natural polysaccharides and their biological activities from natural sources. Then, we discuss some natural polysaccharides with growth factor-binding affinities and inspired polymer tools, focusing on how wound-healing and tissue reparation can possibly benefit from these promising polysaccharides. [ABSTRACT FROM AUTHOR]

The parent and substituted vinoxy radicals are key intermediates in both combustion and atmospheric chemistry. Experiment and theory indicate that vinoxy radicals react with moderate facility with molecular oxygen to form alpha-oxoperoxy radicals.

The yields of OH radicals from the ozonolysis of ethene and trans-2-butene under dry and humid conditions are measured using small-ratio relative rate technique. Master equation calculations are performed for the reactions of the appropriate carbonyl oxide with H2O aid in the interpretation of the experimental results.

The branching ratios for the mentioned R8 reaction were measured for three organic peroxy radicals namely, ethyl peroxy (C2H5O2), acetyl peroxy (CH3C(O)O2), and acetonyl peroxy (CH3C(O)CH2O2) radicals. The atmospheric implications of these branching ratios are discussed.

The yields of OH radicals from the ozonolysis of ethene and trans-2-butene under dry and humid conditions are measured using small-ratio relative rate technique. Master equation calculations are performed for the reactions of the appropriate carbonyl oxide with H2O aid in the interpretation of the experimental results.

The structure of benzoylformate decarboxylase complexed with the (R)-mandelate inhibitor indicates that the hydroxyl group of S26 mediates the binding of benzoylformate and H70 and H281 amino acid residues which function as catalytic acids and/or bases. Data indicate that at least two hydrogen bonds are formed between the substrate and active site side chains and H70A is involved in the catalysis.

Cancer is a devastating disease and is considered number one killer worldwide. Herbal formulations had played a key role over the past several decades in the development of anti-cancer drugs. Medicinal plants, which are endemic in Jordan, are known for several biological activities in particular their anti-cancer activity. However, the anti-cancer efficacy of the root extracts of Jordanian Rubia tinctorum and Alkanna tinctoria is not yet reported. To address this issue, this study assessed the anti-cancer activity of some root extracts obtained from Jordanian R. tinctorum and A. tinctoria in different tumor cell lines including the tongue, bladder, colon, gastric, lungs, breast, pancreas, and renal tissue origins by modified propidium iodide (PI) based monolayer assay. Among the tested root extracts obtained by different solvent systems, A. tinctoria in 100 % ethanol and methanol showed prominent anti-cancer activity against MDA-MB-231breast cancer cells (IC50: 2.98 μg/ml, IC70: 6.03 μg/ml), and CAL-27 tongue squamous carcinoma cells (IC50: 3.86 μg/ml, IC70: 5.97 μg/ml) respectively. Different solvent root extracts of R. tinctorum exhibited a similar trend of anti-tumor activity in both CAL-27 and MDAMB- 231 cells. The anti-proliferative property of the extracts on CAL-27 and MDA-MB-231 cells is unclear. However, it can be concluded that the observed anti-cancer potential can be attributed to the phenolic compounds of the extracts as high polar solvents were used for extraction. The current study forms the rationale for isolating significant amount of anti-cancer active compounds from R. tinctorum and A. tinctoria. [ABSTRACT FROM AUTHOR]

Objective: To investigate different types of dates and medical properties of influencing blood clotting and wound healing in an animal model. Methods: Three different cultivars of dates (Ajwa, Khalas, and Fardh) were examined in-vivo, for blood clotting and wound healing using CD1 mice of both sexes. Study of toxicity to animals was performed accordingly prior to further investigations. The ethanolic extracts were given orally to animals as a constituent in their daily water. Blood samples were obtained from the mice inferior vena cava to carry out the prothrombin time (PT) assay using the manual method and confirmed using a semi-automated machine. The bleeding time (BT) assay was performed using the cutting technique. In the wound healing analysis, a small cut (5-10 mm) in the skin overlying the thigh was conducted in all mice under anesthesia. The diameter of the cut and healing status were measured on a daily basis throughout the time of the experiment using a roller. Results: Ajwa was able to elevate both PT and BT (P<0.05), significantly in a time-dependent manner followed by Khalas date (P<0.05). The results of PT and BT of Fardh date were found to be very close to those of the control group (P<0.05). Despite its activity as an anticoagulant, Khalas date showed a potential property to enhance wound healing in contrast to other dates and the control groups in this study. Conclusions: Omani Khalas date fruit has both antithrombotic as well as wound healing properties. The results open a new gate with these fruits for exploring the potential component(s) that may play an important role in antithrombotic as well as wound healing process. [ABSTRACT FROM AUTHOR]

A report is presented on the discovery of a mechanism-based inhibitor of benzoylformate decarboxylase (BFD) that covalently modifies the enzyme via active site phosphorylation, a type of mechanism-based inactivation. The report highlights that benzoylphosphonate acts as mechanism-based inhibitor BFD, with inactivation resulting from the phosphoryl-action of Ser26.