title: 19F nuclear magnetic resonance studies of structure and function relationships in trifluoroacetonylated rabbit muscle glyceraldehyde-3-phosphate dehydrogenase.
abstract: Specific reaction of Cys-149 with 3,3,3-trifluorobromacetone allows one to probe symmetry relation between the active center regions of tetrameric glyceraldehyde-3-phosphate dehydrogenase by 19F nuclear magnetic resonance (nmr) techniques. Nmr titration studies in the pH range of greatest enzymic activity reveal the existence of species with an (alphaalpha')2 structure; this symmetry is not induced by the coenzyme. Addition of NADH to the ketone-labeled protein causes the enzymic reduction of the ligand in a stereospecific manner and is used to demonstrate the functionality of residues other than Cys-149 that are essential for catalysis. The interpretation of chemical shift characteristics found for the trifluoroacetonyl group together with the kinetics of its reduction allows the derivation of a dynamic model for the enzymic structure which may contribute to understanding of the half-of-the-sites phenomenon.
mesh_terms: D000096:Acetone / Q000031:analogs & derivatives*; D000818:Animals; D001665:Binding Sites; D001894:Borohydrides; D001966:Bromine; D002384:Catalysis; D003553:Cystine / Q000378:metabolism; D005461:Fluorine; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D009132:Muscles / Q000201:enzymology*; D009243:NAD / Q000494:pharmacology; D010084:Oxidation-Reduction; D011817:Rabbits; D013329:Structure-Activity Relationship
chemical_list: D001894:Borohydrides; D009243:NAD; D000096:Acetone; D005461:Fluorine; D003553:Cystine; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D001966:Bromine