title: Localization of tryptophan residues in thiamine pyrophosphate-binding sites of pyruvate dehydrogenase from pigeon breast muscle.
abstract: Interaction of N-bromosuccinimide with the pyruvate dehydrogenase component of the pigeon breast muscle pyruvate dehydrogenase complex results in a rapid and specific modification of two tryptophan residues per mole of the protein and in complete inactivation of the enzyme. Modification of the enzyme excludes the development of the negative Cotton effect with a maximum at 330 nm, characteristic of the charge transfer complex between the protein tryptophan residue and thiamine pyrophosphate. Modification of one tryptophan residue was shown to result in the absence of the band at 330 nm in one of the active centers of pyruvate dehydrogenase, while oxidation of two tryptophan residues excludes the formation of a charge transfer complex in both centers. The conclusion was drawn about the presence in the pyruvate dehydrogenase active centers of two tryptophan residues involved in the formation of the charge transfer complex with the thiazolium ring of thiamine pyrophosphate.
mesh_terms: D000818:Animals; D001665:Binding Sites; D001974:Bromosuccinimide / Q000494:pharmacology; D010856:Columbidae; D007700:Kinetics; D009132:Muscles / Q000201:enzymology*; D010084:Oxidation-Reduction; D011485:Protein Binding; D011768:Pyruvate Dehydrogenase Complex / Q000378:metabolism*; D013835:Thiamine Pyrophosphate / Q000378:metabolism*; D014364:Tryptophan / Q000032:analysis*
chemical_list: D011768:Pyruvate Dehydrogenase Complex; D014364:Tryptophan; D001974:Bromosuccinimide; D013835:Thiamine Pyrophosphate