SUBSTRATE-SPECIFICITY OF ENDO-1, 3-BETA-GLUCANASE FROM ANTARCTIC KRILL EUPHAUSIA-SUPERBA

Two kinds of 1,3-beta-glucanase were found in extracts from frozen Antarctic krill Euphausia superba. One of them was purified to be homogeneous in disc electrophoresis. The amount of reducing sugars produced from laminaran with this enzyme reaction considerably exceeded the amount of liberated glucose. The enzyme hydrolyzed the periodate-oxidized and reduced laminaran. The enzyme also hydrolyzed laminarioligosaccharides except laminaribiose. However, the enzyme could not hydrolyze (1 --> 3)-beta-:(1 --> 4)-beta-D-glucan such as barley glucan and lichenan. These findings indicate that this enzyme belongs to the classes of (1 --> 3)-beta-D-glucan glucanohydrolase (EC 3.2.1.39). This enzyme hydrolyzed laminaritriose, but the enzymes classified to EC 3.2.1.39 were reported to have no ability to hydrolyze laminaritriose. Therefore, 1,3-beta-D-glucan glucanohydrolase isolated in this study has a new property in this respect.