MULTIPLE PHOSPHORYLATION OF ACETYL-COA CARBOXYLASE IN CHICK LIVER-CELLS - CYCLIC AMP-INDEPENDENT PROCESS

  • 1 January 1978
    • journal article
    • research article
    • Vol. 253  (15) , 5267-5269
Abstract
When chick liver cells in monolayer culture were incubated with 32Pi in the presence of insulin, acetyl-CoA carboxylase became extensively labeled with 32Pi reaching a stoichiometry of 9-10 mol of phosphoryl group/mol of 240,000 dalton enzyme subunit. The covalently bound phosphate was found to be metabolically labile, turning over with a t1/2 [half-time] of approximately 2 h (enzyme t1/2 .simeq. 24 h). Addition of dibutyryl cyclic AMP altered neither the rate nor extent of phosphorylation. Contrary to other reports, the fully phosphorylated acetyl-CoA carboxylase appears to be catalytically active.