Characterization of two forms of glucoamylase from aspergillus niger
Characterization of two forms of glucoamylase from aspergillus niger
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黑曲霉两种形式葡糖淀粉酶的表征
DOI：
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发表时间：
1982
期刊：
影响因子：
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通讯作者：
M. Ottesen
中科院分区：
文献类型：
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作者：
B. Svensson;Torben Graves Svendsen;I. Svendsen;T. Sakai;M. Ottesen
尼日尔曲霉葡糖淀粉酶GI和GII（E. C. 3.2.1.3）通过硫酸铵沉淀，然后通过DEAE-纤维素离子交换层析从商业酶制剂中分离。两种酶都由单一糖基化多肽链组成。通过沉降平衡超离心法测定GI和GII的分子量分别为52，000和46，000，通过分子筛法测定GI和GII的分子量分别为65，000和55，000。GI和GII的氨基酸组成非常相似。此外，完整的GI和GII以及它们的氰片段的N-末端氨基酸序列是相同的，这表明两种形式的一级结构具有很大的同源性。此外，还采用高压凝胶渗透色谱法对蜜环菌蛋白酶、金黄色葡萄球菌V8蛋白酶和颌下蛋白酶分别产生的GI和GII酶进行了分析。洗脱曲线也与具有相似多肽链的GI和GII一致。然而，用羧肽酶Y消化显示两种形式的不同C-末端残基。
Aspergillus niger glucoamylases GI and GII (E.C. 3.2.1.3) were isolated from a commercial enzyme preparation by ammonium sulfate precipitation followed by DEAE-cellulose ion exchange chromatography. Both enzymes consist of a single glycosylated polypeptide chain. The molecular weights of GI and GII were determined by sedimentation equilibrium ultracentrifugation to 52,000 and 46,000, respectively, and by molecular sieving to 65,000 and 55,000. The amino acid compositions of GI and GII were very similar. Furthermore, the N-terminal amino acid sequence of the intact GI and GII as well as of their cyanogen fragments were identical, suggesting great homology in the primary structure of the two forms. In addition the digests of GI and GII produced respectively by Armillaria mellea protease, Staphylococcus aureus V8 protease, and submaxillary protease were analyzed by high pressure gel permeation chromatography. The elution profiles were also consistent with GI and GII having similar polypeptide chains. However, digestion with carboxypeptidase Y showed different C-terminal residues of the two forms.