十二烷基苯磺酸钠共振散射光谱法测定木瓜蛋白酶活力

在pH值6.5的磷酸盐缓冲溶液中，十二烷基苯磺酸钠(SDBS)与酪蛋白(Casein)形成缔合物微粒，在470，360，400，420和520 nm产生5个瑞利散射峰。在选定条件下，木瓜蛋白酶(Papain)可水解酪蛋白(Casein)，加SDBS可中止酶催化反应并与未反应的酪蛋白底物结合形成缔合物微粒。随着Papain浓度的增大，470 nm处的共振散射峰强度降低。Papain的酶活力在0.048～4.8 USP·mL-1范围内与ΔI_{470 nm}呈现良好的线性关系。其线性回归方程为ΔI_SDBS=1.972c+2.31，相关系数分别为r=0.999 9，检测限为0.020 USP·mL-1。该法用于嫩肉粉中木瓜蛋白酶活力测定，结果令人满意。

Resonance Scattering Spectral Assay of Papain Enzymatic Activity with Sodium Dodecyl Benzene Sulfonate

In pH 6.5 phosphate buffer solutions, dodecyl benzene sulfonate (SDBS) was combined with casein to form association particles, which exhibited five Rayleigh scattering peaks at 470, 360, 400, 420 and 520 nm, respectively. Under suitable conditions, papain has catalytic effect on the hydrolysis of casein, and SDBS can stop the catalytic reaction and be combined with the excess casein to form association particles. The scattering peak at 470 nm decreased with the activity of papain. The delta I470 value was linear with the papain activity in the range of 0.048-4.8 USP x mL(-1). Its regress equation is delta I(SDBS) = 1.972c + 2.31, with a related coefficient of 0.9999 and detection limit of 0.020 USP x mL(-1). This new assay has been applied to the assay of the papain activity in food additive with satisfactory results.