Reversible phosphorylation of proteins is a post-translational modification that regulates diverse biological processes. The molecular mechanism underlying phosphoryl transfer catalyzed by enzymes, in particular the nature of transition state (TS), remains a subject of active debate. Structural evidence supports an associative TS, whereas physical organic studies point to a dissociative charact...

The phosphoryl group, PO3-, is the dynamic structural unit in the biological chemistry of phosphorus. Its transfer from a donor to an acceptor atom, with oxygen much more prevalent than nitrogen, carbon, or sulfur, is at the core of a great majority of enzyme-catalyzed reactions involving phosphate esters, anhydrides, amidates, and phosphorothioates. The serendipitous discovery that the phospho...

A method is reported for the phosphoryl bond cleavage of O-alkyl phosphinates, phosphinothioates and certain phosphonamidates to furnish the corresponding P(III) borane adducts. The two-step procedure relies upon initial activation of the phosphoryl bond with an alkyl triflate, followed by reduction of the resulting intermediate using lithium borohydride.

Applications of isotopic techniques have contributed considerably to the understanding of kinase mechanisms. Studies with 018 (l-3) have shown that various kinase reactions proceed by transfer of a phosphoryl group without exchange of the phosphoryl oxygens with water or substrates’ Evidence that the kinase reactions do not involve formation of a phosphoryl enzyme intermediate is given by the i...

The Bacillus subtilis sacU locus consists of two genes, degS and degU, which positively regulate the synthesis of several extracellular enzymes including the neutral and alkaline proteases. Both the DegS and DegU proteins have been purified from overproducing Escherichia coli strains harboring degS or degU gene-carrying plasmids, and the following results were obtained. DegS was autophosphoryla...

A protein designated phosphor!// Iransferasr has bee11 isolated from beef heart mitochondria and has been found to increase the ability of suhnlitocllorldrial particles, oxidizing either NASH or snecinatc, to synthesize ,4TP from ADI and inorganic orthophosphate. Increases in the value of P:O ratios between 0.45 and 1 have been observed wit,h srlccinate as snbstrat e. Phosphoryl trnnsferase was...

Applications of isotopic techniques have contributed considerably to the understanding of kinase mechanisms. Studies with 018 (l-3) have shown that various kinase reactions proceed by transfer of a phosphoryl group without exchange of the phosphoryl oxygens with water or substrates’ Evidence that the kinase reactions do not involve formation of a phosphoryl enzyme intermediate is given by the i...