中文摘要：

以PNP—β—xylopyranoside为底物确定小麦麸皮内源性β-木糖苷酶的酶活力测定条件，并对β-木糖苷酶的酶学性质进行研究。试验确定酶活测定条件为底物浓度1mg／mL，提取液pH5。木糖苷酶的酶学性质：最适反应温度为60℃，在20～50℃时稳定性好，保温60min后其活力可保持在70％以上，最适pH值为5，在pH值5～6时对木糖苷酶的破坏力相对较小，保温60min后其活力仍可保持在80％以上。动力学参数Km和Vmax分别为4．518mg／mL，0．392μmol／（min·g）。通过对4种小麦麸皮酶活力进行测定发现：细麸中的β-木糖苷酶活性均高于粗麸，粗麸中郑麦8998的木糖苷酶酶活最大，细麸中花培8号小麦木糖苷酶活性最大。

英文摘要：

Enzyme activity assay conditions and some characteristics of the endogenous β-xylosidase in wheat bran were investigated by taking PNP-β-xylopyranoside as the substrate. Results showed that the substrate concentration was 1 mg/mL, pH value of extract was 5, the optimal temperature and pit were 60℃and 5, respectively, and it had a better thermal stability between 20-50 ℃, the residual ac tivity can be maintained more than 70%. In addition, the residual activity was 80% at the pH 5-6. The kinetic parameters Km and Vmax were 4. 518 mg/mL and 0. 392 μmol/（min · g）. Enzyme activity of four kinds of wheat bran were measured, the study exhibited that the enzyme activity in fine bran were higher than those in coarse bran.