Nk. Nagradova et al., D-GLYCERALDEHYDE-3-PHOSPHATE DEHYDROGENASE - PREEXISTENT ASYMMETRY OFTHE TETRAMER AND ITS FUNCTIONAL IMPLICATIONS, Biotechnology and applied biochemistry, 18, 1993, pp. 157-163
Modification of a single arginine residue per subunit of rabbit muscle
D-glyceraldehyde-3-phosphate dehydrogenase stabilizes the tetramer in
a conformation wherein only two active sites are capable of performin
g catalysis (oxidation Of D-glyceraldehyde 3-phosphate or hydrolysis o
f p-nitrophenyl acetate). The modified enzyme exhibits half-of-the-sit
es reactivity towards iodoacetate and iodoacetamide, known to be 'all-
of-the-sites reagents' with the native enzyme. Evidence is presented s
upporting the model of a built-in asymmetry of the tetramer. The resul
ts obtained suggest that the arginine residue (probably Arg-231) contr
ols the conformational transition between the asymmetric and symmetric
states of the tetramer.