摘要
平邑甜茶叶片在水分胁迫下内肽酶活力的变化可分为低值缓降期和速升期 ,对应于叶绿素含量缓降期和速降期 ,用激活剂和抑制剂处理。结果表明 ,水分胁迫引起叶片老化过程中存在 3种以上的内肽酶 (巯基蛋白酶、丝氨酸蛋白酶和金属蛋白酶 ) ,而在蛋白质降解中起主要作用的是巯基蛋白酶。以牛血红蛋白、酪蛋白为底物时 ,最适 pH为 5 .2 ;以Rubisco为底物时 ,最适pH为 4 .8。这表明水分胁迫在平邑甜茶叶片衰老过程中起主要作用的是酸性蛋白水解酶 ;3种底物内肽酶的最适温度均为 4 5℃。另外 ,用不同浓度放线菌酮、激素、H2 O2 处理的试验表明 ,放线菌酮和BA可抑制内肽酶的活性 ,而ABA和H2 O2 可促进内肽酶活力的提高。
The changes of endopeptidases activities in Malus hupehensis leaves under water stress included two phases, low steady phase and rapid increase phase, which relatively consisted with the changes of chlorophyll contents. Identified by inhibitors (IA, PMSF, EDTA), activator (DTT) and different substrates, there existed more than three subclasses of endopeptidases during leaf aging process, namely thiol proteinases, serine proteinases, and metallo proteinases, and among of them, thiol proteinases was the most active one. The optimum pH for casein?bovine hemoglobin and rubisco were 5.2, 5.2, and 4.8, respectively. Acid endopeptidases played a key role during aging process under water stress. The optimum temperature were all 45℃. The results treated with actidione, ABA, BA, and H 2O 2 also indicated that BA and actidione could inhibited endopeptidases activity. On the other hand, ABA and H 2O 2 could enhance its activity.
出处
《中国农业科学》
CAS
CSCD
北大核心
2002年第12期1514-1518,共5页
Scientia Agricultura Sinica
基金
北京市重点实验室"果树逆境生理与分子生物学实验室"及教育部优秀教师教科奖励基金资助项目
