PERSPECTIVES AND SUMMARY ................... ... ...................................................... 877 Classes of enzyme involving reactions at phosphorus...................................................... 878 COVALENT REACTION INTERMEDIATES, CRYPTIC AND OTHERWISE........................................................................................................ 879 Reactions of Pho...

Quantifying the rate of phosphate monoester dianion hydrolysis under physiological conditions has implications for designing transition state mimics and understanding how catalysis is facilitated. Catalysis is energetically most efficient if the mechanistic pathway in solution is stabilised. Monoesters are believed to have a "dissociative" transition state that has little bonding to the nucleop...

The ArcB and ArcA proteins constitute a two-component signal transduction system that plays a broad role in transcriptional regulation. Under anoxic or environmentally reducing conditions, the sensor kinase (ArcB) is stimulated to autophosphorylate at the expense of ATP and subsequently transphosphorylates the response regulator (ArcA). ArcB is a complex, membrane-bound protein comprising at le...

Synthesis of a series of new 1, 3, 2dioxaphosphinane derivatives (3a-j) was accomplished. The key step in the synthesis of 3a-j involves the cyclization reaction of tris (hydroxy methyl) nitromethane (1) with P(X)Cl3 (X=S,O) in presence of TEA in THF at 40-45 °C to afford the phosphoryl mono chloride intermediate (2). The intermediate (2) when treated with different substituted aromatic amines ...

Phosphagen kinases catalyze the reversible transfer of a phosphoryl group between guanidino phosphate compounds and ADP, thereby regenerating ATP during bursts of cellular activity. Large quantities of highly pure arginine kinase (EC 2.7.3.3), the phosphagen kinase present in arthropods, have been isolated from E. coli, into which the cDNA for the horseshoe crab enzyme had been cloned. Purifica...

Highly substituted polycyclic aromatic and heteroaromatic compounds are produced via a two-stage tandem benzannulation/cyclization strategy. The initial benzannulation step proceeds via a pericyclic cascade mechanism triggered by thermal or photochemical Wolff rearrangement of a diazo ketone. The photochemical process can be performed using a continuous flow reactor which facilitates carrying o...

The compounds benzyloxycarbonyl-L-leucyl-hydroxamate (Z-Leu-NHOH), phosphoryl-L-leucyl-L-phenylalanine (P-Leu-Phe) and 2-mercaptoacetyl-L-phenylalanyl-L-leucine (HSAc-Phe-Leu) strongly inhibit the activity of Pseudomonas elastase in vitro. The capacity of these inhibitors to prevent corneal melting and perforation due to the elastase was examined in rabbit eyes by intrastromal injections of ela...

By use of an asymmetric Ullmann coupling involving chiral naphthalene oxazolines 1, the title compounds were prepared in good yields and with high diastereoselectivity. Hydrolysis of the binaphthyl oxazolines 2 led to the di-aldehydes 5, which were transformed into the azepine derivative, 6. The latter was treated with the appropriate phosphoryl halide to access the chiral HMPA systems 7 and 9....

DL-1-(2,3-Dihydroxypropyl)thymine was prepared by Hilbert-Johnson reaction of 2,4-dinethoxy-5-methylpyrimidine with allyl bromide followed by the osmium tetroxide catalyzed hydroxylation of the l-allyl-4-methoxy-5-methylpyrimidin-2-one obtained as an intermediate. The D-glycero enantiomer, R-1-(2,3-dihydroxypropyl)thymine and the corresponding 1-substituted uracil derivative were prepared from ...

         According to the World Health Organization (WHO), mercury is among one of ten substances that represent a significant health problem. Contamination environment with and its compounds possible through natural artificial ways from ill-conceived or deliberate actions. These include human consumption mercury-contaminated seafood fumes released during...