CHITINOLYTIC ACTIVITY OF COMMERCIALLY AVAILABLE β-GLUCOSIDASE

Abstract

A commercially available β-glucosidase (β-D-glueoside glucohydrolase, E. C. 3.2.1.21) preparation was investigated as a possible alternative to a more expensive commercial chitobiase (chitobiose acetylaminodeoxyglucohydrolase, E. C. 3.2.1.29) for use in chitinase assay. The preparation hydrolyzed N,N 1 -diacetylchitobiose at a rate comparable to the chitobiase, but also hydrolyzed chitin substrates. Regenerated chitin was hydrolyzed to a greater extent with the β-glucosidase preparation alone than when soybean chitinase (chitin glycanohydrolase, E. C. 3.2.1.14) was also included in the reaction. Activity decreased with additional amounts of chitinase in the assay, indicating a competition between the two preparations for the substrate. The β-glucosidase itself may hydrolyze regenerated chitin to a certain extent. The β-glucosidase alone also hydrolyzed microcrystalline chitin and crab shell chitin, with release of N-acetylglucosamine, suggesting the presence of a contaminating chitinase in the β-glucosidase preparation. Further study is indicated in order to determine the limitations of the use of β-glucosidase preparations as sources of chitobiase activity in chitinase assay systems.