研究论文2023年第42卷第1期食品与生物技术学报费嵩禹，等：来源于生孢噬纤维菌的新型β-葡萄糖苷酶SmBgl3A的性质研究CharacterizationofaNovelβ-glucosidaseSmBgl3AfromSporocytophagasp.CX11FEISongyu，WANGZiyi，JINGXiaofeng，YANGFan，CHENXiaoyi*，LIXianzhen（SchoolofBiologicalEngineering，DalianPolytechnicUniversity，Dalian116034，China）Abstract：Aβ-glucosidasegeneSmBgl3A,whichmightplayakeyroleincellobiosedegradationandutilization,wasscreenedfromSporocytophagasp.CX11genomethroughtheanalysisandcomparisonofexpressionlevel.Thegenecontains2283bpandencodes760aminoacids.TheencodedproteinofSmBgl3Ahas46.76%homologywiththeβ-glucosidaseBoGH3BfromBacteroidesovatus.ThegeneSmBgl3AwasheterologouslyexpressedinEscherichiacoli.TheelectrophoreticallypurerecombinantproteinSmBgl3AwasachievedbythepurificationofcrudeenzymesusingNi-NTAaffinitychromatography,andtherelativemolecularweightofrecombinantproteinwasconsistentwiththetheoreticalvalue(8.12×104).CharacterizationofenzymaticpropertiesshowedthattheoptimumtemperatureandpHofSmBgl3Awere35℃and6.5,respectively.When摘要：通过表达水平分析比较，从生孢噬纤维菌Sporocytophagasp.CX11基因组中筛选出在菌株降解纤维二糖过程中起关键作用的β-葡萄糖苷酶基因SmBgl3A。该基因含有2283bp碱基对，编码760个氨基酸，其编码蛋白质与来源于Bacteroidesovatus的β-葡萄糖苷酶BoGH3B同源性为46.76%。将该基因在大肠杆菌中进行异源表达，粗酶液经Ni-NTA亲和层析一步纯化得到电泳级纯度的酶蛋白SmBgl3A，重组蛋白质相对分子质量与理论值（8.12×104）一致。酶学性质表征结果表明，SmBgl3A最适温度和pH分别为35℃和6.5；pH在5.0~7.0、温度在40℃以下时，稳定性较好，同时有着较好的NaCl耐受性。SmBgl3A的最适底物为pNPG，以pNPG为底物时的比活力高达14.74U/mg；Km值为10.88mmol/L，kcat值为46.72s-1。SmBgl3A作为一种新型的、酶学性质优良的β-葡萄糖苷酶，进一步扩展了β-葡萄糖苷酶的种类，为该酶在纤维素降解、食品工业等领域的应用奠定基础。关键词：β-葡萄糖苷酶；GH3家族；生孢噬纤维菌CX11；异源表达；酶学性质中图分类号：Q814文章编号：1673-1689（2023）01-0083-10DOI：10.3969/j.issn.1673-1689.2023.01.007来源于生孢噬纤维菌的新型β...
