Clostridial glycine reductase: protein C, the acetyl group acceptor, catalyzes the arsenate-dependent decomposition of acetyl phosphate.
The highly purified protein C component of clostridial glycine reductase is required in addition to seleno-protein A and protein B for the conversion of glycine to acetate and ammonia in the presence of arsenate. As shown by Arkowitz and Abeles [Arkowitz, R. A. & Abeles, R. H. (1989) Biochemistry 28, 4639-4644], the products are ammonia and acetyl phosphate in the presence of phosphate. The protein C component alone catalyzes an arsenate-dependent decomposition of acetyl phosphate, showing that it serves as the acetyl group acceptor in the overall reaction. A thiol-reducing agent and Mg2+ are required for catalysis of the arsenolysis reaction by protein C. Alkylation or heating at 60 degrees C completely abolishes the ability of protein C to catalyze the arsenolysis reaction and to participate as an essential component in the overall glycine reductase reaction.
Stadtman
T C
TC
Laboratory of Biochemistry, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892.
D000594:Amino Acid Oxidoreductases / Q000302:isolation & purification / Q000378:metabolism*; D001149:Arsenates / Q000494:pharmacology*; D001151:Arsenic / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000302:isolation & purification / Q000378:metabolism*; D003013:Clostridium / Q000201:enzymology*; D004229:Dithiothreitol / Q000494:pharmacology; D007700:Kinetics; D015636:Magnesium Chloride / Q000494:pharmacology; D009097:Multienzyme Complexes / Q000302:isolation & purification / Q000378:metabolism*; D010755:Organophosphates / Q000378:metabolism*; D009943:Organophosphorus Compounds / Q000378:metabolism*
D001149:Arsenates; D001426:Bacterial Proteins; D009097:Multienzyme Complexes; D010755:Organophosphates; D009943:Organophosphorus Compounds; D015636:Magnesium Chloride; C011632:acetyl phosphate; D000594:Amino Acid Oxidoreductases; C020815:glycine reductase; D001151:Arsenic; D004229:Dithiothreitol