title: The stereochemical course of yeast hexokinase-catalysed phosphoryl transfer by using adenosine 5'[gamma(S)-16O,17O,18O]triphosphate as substrate.
abstract: Adenosine 5'[gamma(S)-16O, 17O, 18O]triphosphate has been synthesized and used to determine the stereochemical course of phosphoryl transfer catalysed by yeast hexokinase. The chirality at phosphorus of the D-glucose 6-[16O,17O,18O]phosphate formed was analysed, after cyclization and methylation, by 31P n.m.r. spectroscopy. The phosphoryl transfer was found to occur with inversion of configuration, with a stereoselectivity in excess of 94%. The simplest interpretation of this result is that the phosphoryl group is transferred between substrates in the enzyme-substrate ternary complex by an 'in line' mechanism.
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives* / Q000378:metabolism; D000345:Affinity Labels / Q000378:metabolism*; D006593:Hexokinase / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D010103:Oxygen Isotopes; D010766:Phosphorylation; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D013873:Thionucleotides / Q000378:metabolism*
chemical_list: D000345:Affinity Labels; D010103:Oxygen Isotopes; D013873:Thionucleotides; C022571:adenosine 5'-O-(3-thiotriphosphate); D000255:Adenosine Triphosphate; D006593:Hexokinase