title: Role of arginine in the binding of thiamin pyrophosphate to Escherichia coli pyruvate oxidase.
abstract: The mode of interaction between Escherichia coli pyruvate oxidase and its cofactor, thiamin pyrophosphate (TPP), was studied with the aid of arginine-directed reagents. The enzyme is rapidly inactivated by either phenylglyoxal or 2,3-butanedione, with the cofactor, TPP, offering partial protection against these reagents. The inactivation by phenylglyoxal was found to be reversible. Experiments with [7-14C]phenylglyoxal showed that while several arginine residues react with this reagent, TPP can prevent the labeling of one such residue. Furthermore, inactivation by 2,3-butanedione is attended by at least a 100-fold decrease in affinity of the enzyme for TPP. These results suggest a direct role for arginine in the binding of the cofactor.
mesh_terms: D001120:Arginine / Q000378:metabolism*; D004852:Epoxy Compounds / Q000494:pharmacology; D004926:Escherichia coli / Q000201:enzymology*; D010658:Phenylglyoxal / Q000494:pharmacology; D011771:Pyruvate Oxidase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013835:Thiamine Pyrophosphate / Q000378:metabolism*
chemical_list: D004852:Epoxy Compounds; C007366:diepoxybutane; D001120:Arginine; D011771:Pyruvate Oxidase; D010658:Phenylglyoxal; D013835:Thiamine Pyrophosphate