title: Rabbit muscle D-glyceraldehyde-3-phosphate dehydrogenase: half-of-the-sites reactivity of the enzyme modified at arginine residues.
abstract: Modification of a single arginine residue per subunit of rabbit muscle apo-D-Glyceraldehyde-3-phosphate dehydrogenase does not affect the rate of hydrolysis of p-nitrophenyl acetate catalyzed by the enzyme, but locks the tetramer in a conformation wherein only two active sites are functioning. The modified enzyme also exhibits half-of-the sites reactivity towards iodoacetate and iodoacetamide. On the other hand, its NAD(+)-binding characteristics remain unchanged. Evidence is presented supporting the view that mechanisms of half-of-the-sites reactivity and negative cooperativity in coenzyme binding are different. The results are consistent with a built-in asymmetry of the tetramer and suggest that the arginine residue (probably Arg-231) controls the conformational transition between the asymmetric and symmetric states of the tetramer.
authors.affiliation: A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Russia.
authors.forename: E V
authors.initials: EV
authors.lastname: Kuzminskaya
authors.forename: R A
authors.initials: RA
authors.lastname: Asryants
authors.forename: N K
authors.initials: NK
authors.lastname: Nagradova
mesh_terms: D000818:Animals; D001051:Apoenzymes / Q000378:metabolism*; D001120:Arginine / Q000737:chemistry*; D001665:Binding Sites; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000737:chemistry / Q000378:metabolism*; D006868:Hydrolysis; D007460:Iodoacetamide / Q000378:metabolism; D007461:Iodoacetates / Q000378:metabolism; D019807:Iodoacetic Acid; D007700:Kinetics; D046911:Macromolecular Substances; D009132:Muscles / Q000201:enzymology*; D009243:NAD / Q000378:metabolism; D009596:Nitrophenols / Q000378:metabolism; D011487:Protein Conformation; D011817:Rabbits; D013329:Structure-Activity Relationship
chemical_list: D001051:Apoenzymes; D007461:Iodoacetates; D046911:Macromolecular Substances; D009596:Nitrophenols; D009243:NAD; C008642:4-nitrophenyl acetate; D001120:Arginine; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D019807:Iodoacetic Acid; D007460:Iodoacetamide