Asialofetuin에 대한 Aspergillus oryzae, bovine liver, Saccharomyces fragilis 유래 beta-galactosidase의 반응 조건

The Reaction Conditions of beta-Galactosidases from Aspergillus oryzae, Bovine Liver, and Saccharomyces fragilis to Asialofetuin

The enzymatic properties of beta-galactosidases from Aspergillus oryzae, bovine liver and Saccharomyces fragilis have been studied using enzyme-linked lectin assay based on the RCA120 and BS-II lectins which specifically bind to terminal galactose and G1cNAc residue, respectively. Asialofetuin, a monomeric glycoprotein with approximately 48kDa in molecular weight, was used as a substrate. This glycoprotein contains three N-linked triantennary complex type carbohydrate chains with each of which terminating in Ga1beta1-4GlcNAc (74%). Their optimal pHs were 3.5 and 6.5 (A. oryzae), and 3.5~5.5 (bovine liver and S.fragilis) at 37oC during 24hrs, and the effective concentrations were 0.9, 2.9, and 1.7mg/ml, respectively. The enzyme from A.oryzae requires 100mM Na+ or K+, while the enzyme from bovine liver requires Ba2+ for activity. However all of the three beta-galactosidases were inactivated by SDS and CU2+. These results indicate that the hydrolysis of glycoprotein such as asialofetuin depends on the reaction conditions of beta-galactosidases and some metal ions.