Characteristics of a β-1,3-glucanase fromSpisula sachalinensis as a glycoprotein

The nature of the carbohydrate-peptide bond and the composition of the carbohydrate chain in a β-1,3-glucanase from the marine molluskS. sachalinensis has been investigated. According to the results of the phenol-sulfuric acid method, the neutral sugars amounted to 6.5% of the molecular weight of the enzyme. The composition of the neutral sugars (Glc : Gal : Man 5:2:1) was determined by the GLC method. It was shown that the β-1,3-glucanase molecule contains no uronic or sialic acids. The amount of amino sugars (15% with equal amounts of glucosamine and galactosamine) was established by amino acid analysis. Alkaline degradation led via the β-elimination reaction to the splitting out of 50% of the neutral sugars and showed the existence of an O-glycosidic bond in the enzyme molecule. Various actions on the carbohydrate moiety (periodate oxidation and treatment with glycosidases) caused no appreciable change in the hydrolyzing capacity of the enzyme.