【摘要】 基因工程菌所产生的重组耐高温α-淀粉酶,通过超滤浓缩、脱盐和聚丙烯酰胺凝胶电泳进行纯化,得到电泳纯的耐高温α-淀粉酶.并测得该酶的分子量为63 KD,等电点pI(室温)为5.5,最适pH为6.0~6.5,稳定pH范围为4~11.5.耐高温α-淀粉酶的最适作用温度为90℃,95℃以上活力下降明显,100℃保温30 min仍保留22%的酶活力;金属离子Cu2+、Fe2+、Fe3+、Zn2+及金属鏊合剂EDTA和柠檬酸盐离子对酶活有显著抑制作用,Mn2+、Mg2+有微弱的抑制作用,K+、Ca2+和表面活性剂SDS有微弱的激活作用,而其他一些离子如Na+、Li+则对酶活影响不大.更多还原

【Abstract】 Thermostable and acid-stable alpha-amylase was produced by recombinant transformant pET-28a-αΑ.Then it was purified by ultrafiltration,desalinization and polyacrylamide gels electrophoresis.The molecular weight of the alpha-amylase was 63KD calculated by SDS-PAG.The optimum temperature was 90℃,the optimum pH was 6.0～6.5.The stable pH range was 4～11.5.The pI(room temperature),the optimum temperature,the optimum pH and the stable pH range were 5.5,90℃,6.0～6.5 and 4～11.5 respectively.About 22% of the initial enzyme activity was measured after 0.5h of incubation at 100℃.The activity of the enzyme was strongly inhibited by Cu2+,Fe2+,Fe3+,Zn2+and EDTA,while Na+,Li+ had no effect on it.Mn2+,Mg2+ had a little inhibition and K+,Ca2+ had a little activation on its activity.更多还原