Abstract
A purified laminarinase preparation was obtained from the Antarctic krill Euphusia superba through successive chromatographies on DEAE-Sephadex A25, Sephadex G200, Sephadex G100, and DEAE-Sephadex A50. A purified laminarinase preparation showed a single protein band on disc electrophoresis. Its molecular weight was estimated to be 65, 000-70, 000. The optimum pH of this enzyme was between 4.3-5.0 and this enzyme was stable until 45°C on heating for 10min at pH 5.0. This enzyme hydrolyzed laminaran and laminarioligosaccharides except laminari-biose. The activity was inhibited by Hg2+, N-bromosuccinimide and gluconolactone.
The amounts of reducing sugars produced from laminaran at the initial stages of the reaction with this enzyme considerably surpassed the amounts of liberated glucose. The rate of hydrolysis on the periodate-oxidized and reduced laminaran by this enzyme was comparable to that on un-treated laminaran, This enzyme split laminaran into yield glucose and laminarioligosaccharides. These results indicate that this enzyme is endo-type.
