米糠中脂酶酶学性质的研究

A Study on Enzymatic Properties of Rice Bran Lipase

米糠是一种巨大的可再生利用的资源。但米糠在贮运 ,制油过程中很容易酸败 ,导致品质变劣 ,主要是由于米糠中含有极其活泼的解脂酶。用CaCl2 溶液从脱脂米糠中提取解脂酶 ,经 (NH4 ) 2 SO4 沉淀后 ,获得粗酶 ,用分光光度法测定其活力。解脂酶的酶学性质研究结果表明 :该酶的最适作用温度约为 35℃左右 ,最适pH值为 7.5～ 8.0。脂酶在温度低于 4 0℃ ,pH值为 5～ 9时稳定 ,在 70℃处理 60min或 80℃处理30min后基本完全失活 ;

The rice bran is a great regenerable and utilizable resoure.It is easy to deteriorate in the course of storage,transportation and oil extraction since it contains most active lipase.The lipase extracted from defatted rice bran with calcium chloride solution was purified by ammonium sulfate precipitation.The crude lipase activity was determined by colorimetry.The lipase activity showed its optimum temperature at about 35℃ and the optimum pH between 7.5 and 8.0.It was stable over the pH range from 5 to 9 and below 40℃,but almost completely lost activity by heating 70℃ for 60min or 80℃ for 30min.The enzyme was activated by low concentration of calcium ion.