海枣曲霉糖苷酶类的化学组成

CHEMICAL COMPOSITION OF GLYCOSIDASES FROM ASPERGILLUS PHOENICIS

本文测定的海枣曲霉糖苷酶均为糖蛋白,含糖量分别为:地衣多糖酶7.7%,木聚糖酶X-Ⅱ 5.8%,木聚糖酶X-Ⅲ 3.3%,β-半乳糖苷酶14.3%,β-葡萄糖苷酶16.1%,β-木糖苷酶15.5%。这几个酶的氨基酸组成有较大差异,但也有共同特点,即都含有较多酸性与羟基氨基酸,含His,Met较少。将这些酶的氨基酸组成作成星状图,结果这些酶的星状图互不相同,只有β-葡萄糖苷酶和β-木糖苷酶的星状图之间有一定的相似性。比较海枣曲霉糖苷酶和其他来源的糖苷酶的氨基酸组成的星状图。发现不同来源的同一种酶都有不同程度的相似性,且相似程度与产生菌之间的亲缘关系有很大的相关性。

The glycosidases purified from Aspergillus phoenicis were all glycoproteins, the carbohydrate contents of lichenase, xylanase Ⅱ, xylanase Ⅲ, β-galactosidase, β-glucosidase and β-xylosidase were 7.7%, 5.8%, 3.3%, 14.3%, 16.1% and 15.1%, respectively. Their amino acid compositions were quite different from one another, but all the seven glycosidases contained more acidic and hydroxylic amino acids, and less His, Met. The star diagrams of amino acid compositions of these glycosidases were also quite different from one another, except that of β-glucosidase and β-xylosidase were similar to each other. Compared with the same glycosidases from other sources, we found that the star diagrams of amino acid compositions of the same glycosidases from different sources were similar to one another, and the extent of similarity were related to the relatedness between the glycosidase producing strains.