Capacity for alternating sites cooperativity in catalysis by succinyl-coenzyme A synthetase.

ABSTRACT: Succinyl-coenzyme A synthetase [succinate:CoA ligase (ADP-forming), EC 6.2.1.5] of Escherichia coli in an alpha 2 beta 2 tetramer. A histidyl residue in the alpha subunit is phosphorylated as a catalytic intermediate. It has been suggested [Bild, G. S., Janson, C. & Boyer, P. D. (1980) J. Biol. Chem. 255, 8109--8115] that the mechanism of action of this enzyme involves intersubunit cooperativity in which attachment of substrates at one of the two active sites promotes catalytic events at the other. This scheme would require that the two active sites, although otherwise equivalent, should act alternately. We have prepared a hybrid enzyme species that contains one 35S-labeled alpha subunit (dephosphorylated), one nonradioactive alpha subunit (phosphorylated), and two beta subunits per tetram

SUBMITTER: Wolodko WT 

PROVIDER: S-EPMC319299 | biostudies-literature | 1981 Apr

REPOSITORIES: biostudies-literature