Purification and steady state kinetic mechanism of glycogen synthase-D from human polymorpho-nuclear leukocytes.

The authors' work on the purification and steady state kinetic investigation of the enzyme glycogen synthase D (UDP-glucose: glycogen 4-alpha-glucosyl-transferase, EC 2.4.1.11) from human polymorphonuclear leukocytes is reviewed. The main features of the kinetic mechanism for catalysis of the reaction interconversion of the quaternary enzyme-substrate-activator complexes. The anions interact exclusively with the G-6-P binding site of the enzyme. The dissociation constants for the enzyme-modifier complexes are determined, and a kinetic mechanism for the action of the anions is proposed, leading to activation or inhibition, depending on the concentration of G-6-P.