Uridine-diphosphate-glucose 4-epimerase from saccharomyces fragilis: inactivation by heat and reconstitution of the inactive enzyme

Abstract

UDP-glucose 4-epimerase from Saccharamyces fragilis is rapidly inactivated by heating at 42 °C for 7 min and at 45 °C for 4 min. The effector site. specific for sugar phosphates, is destroyed still earlier. The enzyme is inactivated by the dissociation of NAD from it leaving the dimeric structure unaffected. It call be reactivated by mercaptoetlianol and NAD, both of which are essential for reactivation, and NAD becomes associated with the dimeric protein moiety.