不吸水链霉菌葡萄糖异构酶的物化表征

CHARACTERIZATION OF THE PURIFIED GLUCOSE ISOMERASES OF STREPTOMYCES AHYGROSCOPICUS

葡萄糖异构酶是一种催化葡萄糖异构为果糖的酶。本文用紫外吸收光谱、红外光谱、氨基酸组分分析、聚丙烯酰胺凝胶梯度电泳、SDS-聚丙烯酰胺凝胶电泳、超薄 层聚丙烯酰胺凝胶等电聚焦电泳技术研究了不吸水链霉菌嗜热亚种M1033菌株产生的葡萄糖异构酶的一些物化性质。结果表明由本实验室制备的均一葡萄糖异构酶的A_(280)与A_(260)的比值是1.76。它是由一个亚单位组成的酶分子。最小分子量是49000。pI值是5.2。氨基酸组分与其它来源的葡萄糖异构酶的氨基酸组分相比较有一些差异,其中Glu,Gly,ALa和Leu的含量都此其它异构酶的高,而Met,Trp,Asp,Thr则比其它葡萄糖异构酶的低。

Some enzymatic properties of the purified glucose isomerase of Streptomyces ahygroscopicus were examined by means of different methods, such as ultraviolet spectrum (UV), infrared spectrum (IR), amino acid composition analysis and polyacrylamide gel electrophoresis (PAGE), sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE),0.2mm thin-layer electrophoresis (TLE).The Streptomyces ahygroscopicus glucose isomerase was found to consist of one subunit by SDS-PAGE. The molecular weight of the enzyme determined by polyacrylamide gel electrophoresis in a continuous molecular sieve gradient method was 49700. The pl of the enzyme determined by 0.2mm thin-layer electrophoresis method was 5.2. Large differences were found in the amino acid composition compared with the enzymes from other sources.