The Effect of Temperature, pH, and Salt on Amylase in Heliodiaptomus viduus (Gurney) (Crustacea: Copepoda: Calanoida)
The Effect of Temperature, pH, and Salt on Amylase in Heliodiaptomus viduus (Gurney) (Crustacea: Copepoda: Calanoida)
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温度、pH 和盐对 Heliodiaptomus viduus (Gurney) 淀粉酶的影响（甲壳类：桡足类：Calanoida）
DOI：
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发表时间：
2006
影响因子：
1
通讯作者：
T. Bhattacharya
中科院分区：
文献类型：
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作者：
T. Dutta;M. Jana;Piriti R. Pahari;T. Bhattacharya
从淡水浮游动物Heliodiaptomus viduus（Gurney）中大量获得一种α-淀粉酶（2400 U/g体重），比活力为20.22 U/g蛋白质。部分纯化的酶在70 ℃下仍有活性，在30 ℃时活性最佳。该酶在pH 3.5和8.5之间具有活性，在pH 6.0时具有最大活性。它在30 ℃下保持完全活性2小时，但在60 ℃下2小时后失去活性，在70 ℃下1小时后失去活性。酶活性保留在60%，在2 M NaCl孵育24小时后，而完全的活性被发现在0.5 M NaCl相同的孵育时间。添加Fe ~（2+）、Ba ~（2+）、Co ~（2+）、Ag ~（2+）和Mn ~（2+）等金属离子可使活性提高130%~ 200%，而K ~（2+）和Sn ~（2+）对活性的影响不大。添加Hg ~（2+）和Li ~（2+）可完全抑制淀粉酶活性，而Cu ~（2+）、Mg ~（2+）和Pb ~（2+）则使酶活性降低到原来的5%。可溶性淀粉、直链淀粉和支链淀粉被该淀粉酶完全消化，而糖原被水解至较小程度。在可溶性淀粉的水解过程中，最初，麦芽糖（G2）和麦芽四糖（G4）以相似的量产生，随后是明显更高量（> 80%）的麦芽糖。直链淀粉是最有潜力的底物，Km值为1.82 mg/ml。在非变性PAGE中分子量为50 kDa，未观察到多种形式。
An interesting α-amylase has been obtained in large quantity (2400 U/g of body weight) with specific activity (20.22 U/g protein) from a freshwater zooplankton, Heliodiaptomus viduus (Gurney). Partially purified enzyme showed activity up to 70 oC and demonstrated optimum activity at 30 oC. The enzyme was active between pH 3.5 and 8.5, with maximum activity at pH 6.0. It retained its full activity at 30 oC for 2 h, but became inactive at 60 oC after 2 h, and at 70 oC after 1 h. Enzyme activity was retained at 60% in 2 M NaCl after 24 h incubation, while full activity was found in 0.5 M NaCl for the same duration of incubation. Addition of metal ions like Fe2+, Ba2+, Co2+, Ag2+, and Mn2+ enhanced activity up to 130%-200% of the original activity, while K+ and Sn2+ caused a negligible increase in the activity. Addition of Hg2+ and Li2+ completely inhibited amylase activity, whereas Cu2+, Mg2+, and Pb2+ reduced activity to as little as 5% of original activity. Soluble starch, amylose, and amylopectin were completely digested by this amylase, whereas glycogen was hydrolyzed to a lesser extent. During hydrolysis of soluble starch, initially, maltose (G2) and maltotetraose (G4) were produced in similar magnitude, followed by a distinctly higher amount (> 80%) of maltose. Amylose was the most potential substrate with a Km value of 1.82 mg/ml. The molecular mass was 50 kDa in the Native PAGE and no multiple forms were observed.