雅致放射毛霉3.2778羧肽酶性质及其活性中心结构的研究  

Enzymatic properties of carboxypeptidase from Actinomucor elegans 3.2778

作　　者：付静[1,2] 杨媚[1] 李理[1] 杨晓泉[1] 

机构地区：[1]华南理工大学轻工与食品学院,广东广州510640 [2]陕西理工学院生物科学与工程学院,陕西汉中723001

出　　处：《中国酿造》2010年第3期30-33,共4页China Brewing

基　　金：国家自然科学基金(30770056)

摘　　要：固态发酵雅致放射毛霉菌株(Actinomucor elegans)3.2778得到羧肽酶粗酶液,以N-苄氧羰酰基-L-苯丙胺酰-L-亮氨酸(N-CBZ-Phe-Leu)为底物,采用镉-茚三酮法测定羧肽酶水解产物。结果表明:雅致放射毛霉3.2778羧肽酶最适作用pH值范围为6.5～7.2,最适作用温度范围在40℃～45℃,最适作用温度为40℃,在30℃～40℃具有良好的温度稳定性。0.99mmol/L金属离子中,Mg2+对羧肽酶活力表现出显著的促进作用,酶活提高37%;而Cu2+、Fe2+、Fe3+、Hg2+可以抑制绝大部分酶活,残留的相对酶活力约10%。9.1mmol/L金属蛋白酶抑制剂1,10-邻菲啰啉(OP)和丝氨酸蛋白酶抑制剂苯甲基磺酰氟(PMSF)和二异丙基磷酰氟(DFP)均可以完全抑制该酶活性,同时,对巯基有修饰作用的蛋白酶抑制剂PCMB、DTT、碘乙酸和β-巯基乙醇对羧肽酶有强烈的抑制作用。因此,推断该酶可能是一种丝氨酸羧肽酶,其活性中心有丝氨酸残基和二硫键结构,酶活受Mg2+激活。Studies on carboxypeptidase characteristics of extracted solution produced by Actinomucor elegans 3.2778 in solid state fermentation of wheat bran were conducted, with the synthetic substrate N-terminal blocked peptide N-CBZ-Phe-Leu and Cd-ninhydrin method. The results showed that maximum carboxypeptidase activity was observed at pH 6.6 and 40℃ respectively. The enzyme was activated between pH 5.0 and 9.5 and was found to be unstable above 45℃. It was activated by Mg^2＋ at 0.99 mM and 9.10 mM, however, partially inhibited by Ca^2＋, Zn^2＋, Ba^2＋, Mn^2＋ at two concentrations. The carboxypeptidase activity was completely inhibited by 1,10- phenanthroline, as well as PMSF and DFP.

关 键 词：雅致放射毛霉 羧肽酶 酶学性质 抑制剂 

分 类 号：TS201.3[轻工技术与工程—食品科学]