Studies of activity and stability of immobilized beta-N-acetylhexosaminidase

Influence of chemical modification on enzyme inactivation kinetics and stability

Enzymes are placed in different categories depending on the effect of chemical modification on their inactivation kinetics and residual activity. This is done using a series-type mechanism involving degraded but stable enzyme states. The major distinction in the three basic categories is the effect of modification on residual activity. Each category is further sub-divided depending on the effect of modification on the values of the deactivation rate constants. The classification provides for a framework for comparison of a wide variety of enzyme deactivation data. Structure-function relations are provided wherever possible.

Hydrolysis of galactose from glycolipids and glycoprotein by young rat brain beta-galactosidases immobilized to Sepharose 4B

An extract of glycosidic enzymes from young rat brain was immobilized to cyanogen bromide-activated Sepharose 4B. Most glycosidases retained approximately 10--25% of their activities after immobilization. Immobilized beta-galactosidases were used repeatedly without detectable loss of enzyme activity in the hydrolysis of p-nitrophenyl-beta-D-galactopyranoside. In addition to the synthetic substrate, the immobilized rat brain beta-galactosidases could also hydrolyze galactose from lactose, galactosylcerebroside, asialofetuin, and GM1-ganglioside. The hydrolysis of GM1- to GM2-ganglioside was confirmed on TLC.