Department de Bioquímica i Biologia Molecular, Universitat de València, Avda. Doctor Moliner 50 E-46100-Burjassot, Valencia, Spain.
Plant Physiol. 1990 Apr;92(4):1070-4. doi: 10.1104/pp.92.4.1070.
The activities and changes in the levels of exopeptidase and endopeptidase activities were characterized in unpollinated ovaries of Pisum sativum L. cv Alaska during senescence and early fruit development induced by gibberellic acid (GA(3)). Two aminopeptidases and one iminopeptidase were electrophoretically separated. These peptidases were sensitive to inhibitors of sulfhydryl proteases. Carboxypeptidase activity was inhibited by phenylmethyl sulfonyl fluoride. An azocasein-degrading endopeptidase, sensitive to thiol protease inhibitors, was also found. An increase in the specific activity of aminopeptidase during both fruit development and ovary senescence was observed. In contrast, the specific activity of carboxypeptidase and endopeptidase increased only during senescence of the ovary. Changes in exopeptidase activity in senescing ovaries could be mainly the consequence of a greater stability to proteolysis while the rise in endopeptidase activity appeared to be due to new or increased synthesis of the enzyme. These results suggest that endopeptidase, and not amino or carboxypeptidase, plays a key role in the senescence of pea ovaries and that the changes in unpollinated ovaries leading to ovary senescence or fruit development can be controlled by gibberellins.
在未授粉的豌豆（Pisum sativum L. cv Alaska）中，研究了赤霉素（GA(3)）诱导的衰老和早期果实发育过程中外肽酶和内肽酶活性的变化。通过电泳分离出两种氨肽酶和一种亚氨肽酶。这些肽酶对巯基蛋白酶抑制剂敏感。羧肽酶活性被苯甲基磺酰氟抑制。还发现了一种对硫醇蛋白酶抑制剂敏感的分解酪蛋白的内肽酶。在果实发育和子房衰老过程中，氨基肽酶的比活力都增加了。相比之下，羧肽酶和内肽酶的比活力仅在子房衰老过程中增加。衰老子房外肽酶活性的变化可能主要是由于对蛋白水解的稳定性增加所致，而内肽酶活性的增加似乎是由于该酶的新合成或增加所致。这些结果表明，内肽酶而不是氨基肽酶或羧肽酶在豌豆子房衰老过程中起关键作用，并且导致子房衰老或果实发育的未授粉子房的变化可以被赤霉素控制。
