Zhang Peng, Wang Fei, Zhang Lie-Feng, Rui Qi, Xu Lang-Lai
College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China.
Zhi Wu Sheng Li Yu Fen Zi Sheng Wu Xue Xue Bao. 2006 Oct;32(5):593-9.
The role of serine endopeptidase in cucumber leaf senescence was studied by using the inhibitor of serine endopeptidase and plant growth regulators (6-BA and ABA) on darkness-induced cucumber leaves. The results showed that the senescence of cucumber leaves were delayed by AEBSF [4-(2-aminoethyl) benzenesulfonyl fluoride hydrochloride], an inhibitor of serine-type endopeptidase, or 6-BA treatment. The chlorophyll contents increased by AEBSF (Fig.3) and the protein degradation of leaves under AEBSF treatment declined more slowly than in the control or under ABA 50 micromol/L treatment (Fig.4), partly because the activities of serine endopeptidases became lower during senescence. However, the activities of endopeptidase in cucumber leaf were increased by ABA 50 micromol/L (Fig.2A), furthermore, the MDA content were also influenced by AEBSF and plant growth regulators (Fig.5). Native gradient PAGE showed that six bands of isoenzymes were detected in cucumber leaves and four bands of which were the type of serine-endopeptidase (Fig.1), and proved that the activities of serine-endopeptidase were inhibited by AEBSF, but enhanced by ABA (Fig.2B) in the leaves. It implies that serine endopeptidases might play an important role in cucumber leaf senescence.
通过使用丝氨酸内肽酶抑制剂以及植物生长调节剂（6-苄氨基腺嘌呤和脱落酸）处理黑暗诱导衰老的黄瓜叶片，研究了丝氨酸内肽酶在黄瓜叶片衰老中的作用。结果表明，丝氨酸型内肽酶抑制剂AEBSF[4-（2-氨基乙基）苯磺酰氟盐酸盐]或6-苄氨基腺嘌呤处理可延缓黄瓜叶片的衰老。AEBSF处理使叶绿素含量增加（图3），且AEBSF处理下叶片的蛋白质降解比对照或50 μmol/L脱落酸处理下降得更慢（图4），部分原因是衰老过程中丝氨酸内肽酶的活性降低。然而，50 μmol/L脱落酸使黄瓜叶片内肽酶的活性增加（图2A），此外，丙二醛含量也受AEBSF和植物生长调节剂的影响（图5）。非变性梯度聚丙烯酰胺凝胶电泳显示，在黄瓜叶片中检测到6条同工酶带，其中4条为丝氨酸内肽酶类型（图1），并证明AEBSF抑制叶片中丝氨酸内肽酶的活性，但脱落酸可增强其活性（图2B）。这表明丝氨酸内肽酶可能在黄瓜叶片衰老中起重要作用。
