THERMOSTABILIZATION OF Eupenicillium erubescens AND Cryptococcus albidus α -L-RHAMNOSIDASES BY CHEMICAL REAGENTS

The aim of the research was a comparative study of the thermal stability of native and modified by various methods α-L rhamnosidases of Eupenicillium erubescens and Cryptococcus albidus for improving the stability of enzymes. Denaturation of native and modified enzymes were performed at 65 0C, pH 5.2. Enzyme activity was determined using p-nitrophenyl-α-L-rhamnopyranoside and naringin. It is found that in the treatment by polyethylenglycol PEG 1500, dextrans 500 and 70 T thermostability of α-L-rhamnosidases tested decreases, while modification with polyethylenglycol 20000 leads to increase thermal stability of the E. erubescens enzyme to 280% and C. albidus to 150%. Comparative study of the thermal stability of the native and modified by cellulose and its derivatives α-L-rhamnosidases of C. albidus and E. erubescens showed that at concentrations cellulose of 5?15 μg/10 μg protein protective effect of polymers on enzymes was investigated was observed. Hydrophobic modifications using succinic anhydride also can slow down the denaturation of α-L-rhamnosidases tested under experimental conditions. These stabilized C. albidus and E. erubescens α-L-rhamnosidases can be used in biotechnological processes.