摘要
从红藻中筛选获得一株能产生明显液化现象并具有较高琼脂糖酶活力的菌株Ag-1,经生理生化实验和16S rDNA序列分析鉴定为弧菌属（Vibrio sp.）.酶学性质研究表明,该酶的最适反应温度为50℃,40～50℃水浴保温1h可保持68％以上的酶活力;最适反应pH值为8.0,在pH 7.0 ～8.0保温1h可保持90％以上的酶活力,在pH 8.0 ～9.0保温1h仍可保持70％以上的酶活力,具有较好的耐热性和耐碱性;且该酶对琼脂底物具有高度专一性;K＋、Ca2＋、Mg2＋、Li＋和Fe3＋对琼脂糖酶活力具有激活作用,Mn2＋、Zn2＋和Cu2＋对琼脂糖酶具有抑制作用.酶反应动力学实验结果表明,该酶的最适底物浓度为8 mg· mL-1,动力学参数Km为0.58mg· mL-1,vmax为3.29 U·mg-1.
A wide -type strain, with apparent liquefied phenomenon and high agarase activity was isolated from red -algae. The strain was identified as Vibrio sp. by its physiological and biochemical experiments, and sequence analysis of 16S rDNA. The optimum reaction temperature of the agarase was 50 ℃, and the agarase maintained more than 68% of its maximum activity after incubation for 1 h under 40 - 50℃. The optimum reaction pH of the agarase was g. O, and the agarase retained more than 90% and 70% of its maximum activity after incubation for lh at the pH range of 7.0 - 8.0 and 8.0 - 9.0, respectively. The enzyme had good heat and alkali resistance and high substrate specifici- ty. Agarase was significantly activated by K＋ , Ca2＋ , Mg2 ＋ , Li＋ and Fe3＋ and strongly inhibited by Mn2 ＋ , Zn2 ＋ and Cu2＋. The results of the enzymatic reaction kinetics showed that the optimal concentration of substrate was 8 mg - mL-1 , and the enzyme kinetic parameters Km and Vmax were O. 58 mg mL-1 and 3.29 U mg-1, respectively.
出处
《福州大学学报（自然科学版）》
CAS
北大核心
2015年第2期278-284,共7页
Journal of Fuzhou University(Natural Science Edition)
基金
国家海洋局海洋公益性行业科研项目(201305015)
福建省海洋高新产业发展专项项目(闽海渔高新[2014]13号)
关键词
琼脂糖酶
海洋微生物
筛选鉴定
酶学性质
动力学参数
agarase
marine microorganism
isolation identification
enzymatic properties
kinetic parameters
