Effect of dextran and its derivatives on thermal inactivation of glucoamylase.

The thermal stability of glucoamylase* [α-1, 4:1, 6-glucan-4:6-glucohydrolase, EC 3.2.1.3] from Rhizopus niveus has been investigated in the presence of dextran, DEAE-dextran, dextran sulfate, polyethylene glycol and Ficoll in a temperature range from 52.0 to 60.0°C in relation to kinetics. Protective effect of dextran against thermal inactivation of the enzyme was pronounced. Dextran, polyethylene glycol and Ficoll, being electroneutral polymers, showed distinct features. The protective effects of these polymers increased in the order: polyethylene glycol