Rabbit muscle D-Glyceraldehyde-3-phosphate dehydrogenase: Half-of-the-sites reactivity of the enzyme modified at arginine residues

• Published in: Biochemical and biophysical research communications Vol. 187; no. 2; pp. 577 - 583
• Main Authors: Kuzminskaya, Elena V., Asryants, Regina A., Nagradova, Natalia K.
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 16.09.1992; Elsevier
• Subjects: Analytical, structural and metabolic biochemistry; Animals; Apoenzymes - metabolism; Arginine - chemistry; Binding Sites; Biological and medical sciences; chemical modification; enzymatic activity; Enzymes and enzyme inhibitors; Fundamental and applied biological sciences. Psychology; glyceraldehyde-3-phosphate dehydrogenase; Glyceraldehyde-3-Phosphate Dehydrogenases - chemistry; Glyceraldehyde-3-Phosphate Dehydrogenases - metabolism; Hydrolysis; Iodoacetamide - metabolism; Iodoacetates - metabolism; Iodoacetic Acid; Kinetics; Macromolecular Substances; muscles; Muscles - enzymology; NAD - metabolism; Nitrophenols - metabolism; Oxidoreductases; Protein Conformation; Rabbits; reactivity; Structure-Activity Relationship; IAA; MOPS; MES; pNPA; IAM; GPDH; Vertebrata; Chemical modification; Mammalia; Structure activity relation; Enzyme; Glyceraldehyde-phosphate dehydrogenase; Apoenzyme; Rabbit; Muscle; Lagomorpha
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/0006-291X(92)91233-G

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.