桔橙小单孢菌产几丁质脱乙酰酶的酶学性质研究

Enzymatic properties of chitin deacetylase from Micromonospora aurantiaca

从海边红树林虾场土壤中筛选的一株产几丁质脱乙酰酶(CDA)的放线菌桔橙小单孢菌(Micromonospora aurantiaca),研究其产CDA的酶学性质。结果表明,CDA的十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)电泳结果显示为单一条带,分子质量为81.8 ku。最适pH值为7.0;最适温度为40℃;Ca^(2+)对此CDA酶活有促进作用,而Cu^(2+)、Zn^(2+)、Mg^(2+)表现出了抑制作用。CDA对虾壳来源的几丁质有明显的脱乙酰效果,红外光谱测得样品脱乙酰度由39.03%提高至78.40%。扫描电镜发现CDA酶解过的几丁质样品表面疏松多孔、出现凹槽、晶体消失,进一步印证了该酶的良好脱乙酰效果,也力证了该酶拥有较好的特性。

A chitin deacetylase （CDA）-producing actinomyces Micromonospora aurantiaca was screened from the seaside mangrove shrimp farms soil, and the enzymatic properties of CDA were researched. The results of sodium dodecyl sulfate polyacrylamide gel electrophoresis （SDS-PAGE） showed that molecular mass of CDA was 81.8 ku for a single band. The optimal pH and temperature were 7.0 and 40 ℃, respectively. Ca^2＋ had promoting effect on CDA enzyme activity, whereas Cu^2＋, Zn^2＋ and Mg^2＋ showed inhibitory effect. CDA had obvious deacetylation effect on chitin from shrimp shells. The degree of deaeetylation of the sample was increased from 39.03% to 78.40% by infrared spectroscopy. By scanning electron microscope, the surface of chitin samples by CDA hydrolysis became loose, porous, grooves and the crystal disappeared, which further evidenced that the CDA had good deacetylation effect and characteristics.