茶树鲜叶中β-葡萄糖苷酶提取条件的研究

Study on the extraction conditions ofβ?glucosidase in fresh leaves of tea plant

研究了从茶树鲜叶中提取 β 葡萄糖苷酶时不溶性聚乙烯吡咯烷酮 (polyvinypolypyrrolidone ,PVPP)的加入量、缓冲液的选择、多酚类浓度对酶活性的影响及酶的部分特性。结果表明 :加入与鲜叶重量相等的PVPP可获得较高的酶活性 ;选用 0 1mol/L (离子强度为 0 7)的柠檬酸—柠檬酸钠缓冲液 (pH 6 0 )作为提取缓冲液可得到活性较高的酶液 ;浓度仅为 4mg/L的茶叶多酚类物质能使酶完全失活 ;β 巯基乙醇和EDTA对酶活性有抑制作用 ;而甘油能提高酶活性 ,2～2 5mol/L的甘油效果较明显 ;

Effects of amount of PVPP,different buffers and polyphenol concentration on the β?glucosidase activity were studied when the enzymes were extracted from fresh leaves of tea plant.The results showed that a suitable amount of PVPP for extracting enzyme is equal to that of fresh leaves.The enzyme presented higher activity with 0 1 mol/L(ion strength 0 7)citrate buffer(pH 6 0)comparatively,but tea polyphenol(4 mg/L)inhibited the enzyme activity completely,β?mercaptoethanol and EDTA could also inhibit its activity.However glycerol was beneficial to its stability and could obviously protect its activity,especially in 2?2 5 mol/L.The β?glucosidase activity was little affected by NaCl.