【摘要】 用中性0.1M焦磷酸钠提取,经硫酸铵分段,丙酮沉淀,从土壤中获得了具有蛋白酶活性的酶-腐殖质复合物,其特性:反应最适pH为9.0,反映最适温度为50°—60℃,温度系数Q₁₀（17°—40℃）为1.93,K_m值为0.97—1.00毫克酪素/毫升,V_max值为74.91—75.35毫克酪氨酸/克·24小时,与原位土壤蛋白酶相比,反应最适pH往碱性偏移,反应最适温度及K_m值变小,热稳性降低,Q₁₀和V_amx值增大。土壤经超声波分散后,可以用各种盐缓冲液将其中具有蛋白酶活性的酶-腐殖质复合物提取出来,其收率依次为水<0.1M磷酸盐-0.3M KCl-0.01MEDTA<三羟甲基氨基甲烷（pH7）<0·2M碳酸氢钠<0.05 M磷酸盐-柠檬酸<0.1M焦磷酸钠溶液。更多还原

【Abstract】 The extraction of the enzyme-humus complexes with protease activity from soil using a series buffered extractants was studied. It was shown that the extraction of 0.1 M pyrophosphate （pH 7.0） was most efficient. Some characteristics of the extracted enzyme were different from those of the enzyme measured in soil. The reasults also showed that the K_m value （0.97—1.0mg casein/ml） and optimum temperature （50—60℃） for the extracted enzyme were lower than those of the enzyme in soil and the V_max value （74.91—75.35mg tyrosine/g·24hr.） optimum pH（9） and temperature coefficient （1.93） were higher than those of the enzyme in soil.The effectiveness of the extractants was in order of distilled water<0.1 M phosphate （pH 7.0） -0.3 M KCl -0.01 M EDTA<Tris （pH 7.0）<0.2 M NaHCO₂<0.05 M phosphate-citrate （pH 7.0）<0.1M Na-Pyrosphate （pH 7.0）.更多还原