摘要
以硝基苯酚-木糖苷为底物,在底物浓度为1 mg/ml ,提取液pH值为5的条件下,测定了小麦麸皮内源性β-木糖苷酶的酶活力,并对4种小麦麸皮内源性β-木糖苷酶的酶学特性进行了比较。结果表明:不同品种小麦麸皮内源性β-木糖苷酶的酶活力不同,同种小麦的粗麸皮和细麸皮中的内源性β-木糖苷酶的酶活力也不同;细麸皮中β-木糖苷酶的酶活力均高于粗麸皮中β-木糖苷酶酶活力,粗麸皮中郑麦8998的β-木糖苷酶酶活力最大,细麸皮中花培8号小麦β-木糖苷酶酶活力最大;郑麦8998、花培8号、郑麦366、郑麦90234种小麦粗麸皮内源性β-木糖苷酶的最适反应温度分别为60、50、50和60℃;最适反应pH值均为5;花培8号和郑麦366两种小麦粗麸皮内源性β-木糖苷酶在20~50℃范围内,酶活力稳定性较好,而郑麦8998和郑麦9023两种小麦粗麸皮内源性β-木糖苷酶在20~60℃范围内,温度对β-木糖苷酶的酶活力影响较小;4种小麦粗麸皮内源性β-木糖苷酶在pH值为5~6时,酶活力稳定性较好;Ca2+、Co2+促进β-木糖苷酶的酶活力,而Ag+对β-木糖苷酶的酶活力有较强的抑制作用。
Enzyme activities of the endogenousβ-xylosidase in wheat bran were investigated in the experiment under the followingconditions:PNP-β-Xylopyranoside (PNPX)were used as the substrate with 1 mg/ml of substrate concentration and 5for pH value of the extracts.Enzymatic characteristics of endogenousβ-xylosidase in 4 types of wheat bran were compared.Results showed that:enzyme activities varied from different varieties of wheat bran;Differences were also found in the enzymeactivity for both coarse and fine wheat bran in the same kind;the enzyme activity in fine bran was observed higher than those incoarse bran.The maximum enzyme activity ofβ-xylosidase was found both in the coarse bran of wheat variety-zhengmai 8998and the fine bran of wheat variety-huapei 8;60℃,50℃,50℃and 60℃was the optimum reaction temperature of theendogenousβ-xylosidase for wheat varieties zhengmai 8998,huapei 8,zhengmai 366 and 9023 respectively;pH 5 was also oneof the optimal reaction conditions for the 4 varieties;For coarse bran in wheat huapei 8 and zhengmai 366,a better enzymeactivity of endogenousβ-xylosidase was got within 20~50℃,while 20~60℃was for coarse bran of wheat zhengmai 8998 and9023;Impact of temperature was not significant in the enzyme activity of endogenousβ-xylosidase;Moreover,a better enzymestability was achieved for all the 4 wheat varieties when the pH value was in the range of 5~6.Ca2+,Co2+were proved to promotethe enzyme activity,while Ag+led an inhibiting role in this regard.
出处
《粮食与饲料工业》
CAS
北大核心
2014年第12期10-14,共5页
Cereal & Feed Industry
基金
国家自然科学基金项目(31071597)
北京市属高等学校人才强教计划资助项目(PHR201107151)
关键词
小麦麸皮
内源性β-木糖苷酶
酶活力
酶学特性
wheat bran endogenousβ-xylosidase enzyme activity enzymatic characteristic