嗜盐菌碱性淀粉酶特性研究

STUDY ON SOME PROPERTIES OF AN ALKALINE AMYLASE FROM HALOBACTERIUM SP H 371

碱性嗜盐菌ＨａｌｏｂａｃｔｅｒｉｕｍｓｐＨ－３７１产生的淀粉酶经超滤、硫酸铵沉淀和ＤＥＡＥ－纤维素纯化后，ＳＤＳ－ＰＡＧＥ凝胶电泳为一条带，分子量为２７０００，等电点３．７，最适反应ｐＨ９．０，最适反应温度６５℃．ＮａＣｌ是维持酶活性的必需因子，酶解产物为麦芽糖、麦芽三糖。

An alkaline amylase has been discovered in culture medium of an alkalophilic Halobacterium sp H 371 isolated from alkali saline soil. The amylase was purified to give a single band on SDS polyacrylamide gel electrophoresis. The amylase has following properties: molecular weight 27 000, isoelectric point (PI) 3 7, optimum pH 9 0, optimum temperature 65 ℃, pH stability 8～12, heat stability below 70 ℃. NaCl is an essential factor for the enzyme activity. End products from soluble starch are maltose, maltotliose, maltotrtraose, maltopentaose.