嗜麦芽窄食单胞菌NTa碱性β-琼脂酶的特性及酶解产物

Characterization of an alkaline β-agarase from Stenotrophomonas sp. NTa and the enzymatic hydrolysates.

作者信息

Zhu Yanbing, Zhao Rui, Xiao Anfeng, Li Lijun, Jiang Zedong, Chen Feng, Ni Hui

机构信息

College of Food and Biological Engineering, Jimei University, Xiamen 361021, China; Fujian Provincial Key Laboratory of Food Microbiology and Enzyme Engineering, Xiamen 361021, China; Research Center of Food Biotechnology of Xiamen City, Xiamen 361021, China; Key Laboratory of Systemic Utilization and In-depth Processing of Economic Seaweed, Xiamen Southern Ocean Technology Center of China, Xiamen 361021, China.

College of Food and Biological Engineering, Jimei University, Xiamen 361021, China.

出版信息

Int J Biol Macromol. 2016 May;86:525-34. doi: 10.1016/j.ijbiomac.2016.01.106. Epub 2016 Feb 2.

DOI:10.1016/j.ijbiomac.2016.01.106

PMID:26836616

Abstract

An extracellular agarase from marine bacterium Stenotrophomonas sp. NTa was purified to homogeneity. By size exclusion chromatography and SDS-PAGE analysis, the enzyme was determined to be a homodimer with monomeric molecular mass of 89.0 kDa. The optimal temperature and pH of strain NTa agarase were 40 °C and 10.0, respectively. It exhibited striking stability across a wide pH range of 5.0-11.0. Agarase from Stenotrophomonas sp. NTa had a relatively good resistance against the detected inhibitors, detergents and urea denaturant. The Km and Vmax for agar were 11.3mg/ml and 25.4 U/mg, respectively. Thin layer chromatography analysis, mass spectrometry, and enzyme assay using p-nitrophenyl-α/β-D-galactopyranoside revealed that strain NTa agarase was a β-agarase that degraded agarose into neoagarobiose, neoagarotetraose and neoagarohexaose as the predominant products, as well as a small amount of 3,6-anhydro-α-L-galactose. This is the first to present evidence of agarolytic activity in strain from genus Stenotrophomonas.

摘要

从海洋细菌嗜麦芽窄食单胞菌NTa中纯化出一种胞外琼脂酶，使其达到同质。通过尺寸排阻色谱和SDS-PAGE分析，确定该酶为同型二聚体，单体分子量为89.0 kDa。菌株NTa琼脂酶的最适温度和pH分别为40℃和10.0。它在5.0-11.0的宽pH范围内表现出显著的稳定性。嗜麦芽窄食单胞菌NTa的琼脂酶对检测到的抑制剂、去污剂和尿素变性剂具有相对较好的抗性。琼脂的Km和Vmax分别为11.3mg/ml和25.4 U/mg。薄层色谱分析、质谱分析以及使用对硝基苯基-α/β-D-吡喃半乳糖苷的酶活性测定表明，菌株NTa琼脂酶是一种β-琼脂酶，它将琼脂糖降解为新琼脂二糖、新琼脂四糖和新琼脂六糖作为主要产物，以及少量的3,6-脱水-α-L-半乳糖。这是首次报道嗜麦芽窄食单胞菌属菌株具有琼脂分解活性的证据。