【摘要】 木瓜蛋白酶ＰＰＡⅢ自水解作用王秀艳，周慧，葛玉斌，李惟（吉林大学分子生物学系，长春１３００２３）ＰＰＡⅢ、ｐａｐａｉｎ、ｐｅｐｓｉｎｅ、ｓｔｅｍｂｒｏｍｅｌａｉｎ等都属于以Ｃｙｓ－ＳＨ为活性中心的酶，同种分子之间存在着一种相互切割的趋势，称为酶自水解...更多还原

【Abstract】 A proteolytic enzyme called papaya protenase Ⅲ was produced from the latex of papaya by CM-cellulose chromatography. Autodigestion of enzyme (2 mg/ml) was investigated at the condition of 1 mmol/L DDT, PH 8. 0, 25℃. During the autodigestion, the activity cruves of the enzyme against casein and BAEE were totally different. The highest proteolytic activity appeared after incubation for 6 hours. Its specific activity was about 2 times of that before autedigestion. The sample was applied to a column of Sephadex G-100, after the autodigestion was stopped by iodoacetic acid. There were two active component peaks appeared on the chromatography.Their molecular weights were 21 800 and 18 000 respectively. The amino terminal residues were Thr and His respectively. About 41 amino acids from the PPAⅢ were cleaved off through autodigestion and the remaining part showed higher proteolytic activity.更多还原