Analysis fo the role of a novel ovarian protein during oocyte maturation using genetic engineering procedures

从猪卵巢卵泡液中分离出一种80kDa的卵泡蛋白酶。该酶可水解合成和天然肽底物的内部Arg-X键，与人血浆钾激肽激酶高度同源。该酶被抑酶蛋白、苄脒、胰肽、止痛药和氟磷酸二异丙基强烈抑制，表明它是一种丝氨酸蛋白酶。研究发现，人单链组织型纤溶酶原激活物可有效地转化为双链形式。这一发现表明丝氨酸蛋白酶参与触发蛋白水解级联纤溶酶原激活剂/纤溶酶系统的激活，这通常被认为在排卵期间卵泡破裂中起作用。从该液中分离出猪丙素。它很容易被胰蛋白酶激活。研究还表明，猪卵巢卵泡液中含有促卵泡素活化酶活性。体外受精过程中获得的人卵巢卵泡液含有一种类似于猪卵泡素的酶，用合成的含精氨酸内肽酶底物检测到。纯化和特性研究表明该酶为血浆钾激肽酶。血浆钾激肽与蛋白酶抑制剂α 2-巨球蛋白相关，被证明是液体中酶的主要形式，表明酶活性受抑制剂调节。该研究还表明，卵泡液中存在的血浆钾激肽可能来自肝脏。

A 80kDa proteinase, follipsin, was isolated from the follicular fluid of porcine ovaries. The enzyme hydrolyzed internal Arg-X bonds of synthetic and natural peptide substrates, and was highly homologous wiht human plasma kallikrein. The enzyme was strongly inhibited by aprotinin, benzamidine, leupeptin, antipain, and diisopropylfluorophosphate, indicating that it is a serine proteinase. It was found that human single-chain tissue-type plasminogen activator was efficiently converted to its two-chain form by the enzyme. The finding suggests the involvement of the serine proteinase in triggering the activation of proteolytic cascade plasminogen activator/plasmin system, that is generally thought to operate in follicle rupture during ovulation.Porcine profollipsin was isolated from the fluid. It was readily activated by trypsin treatment. The study also showed that the follicular fluid of porcine ovary contains a profollipsin-activating enzyme activity.Follicular fluid from human ovaries obtained in in vitro fertilization procedure contained an enzyme similar to porcine follipsin as detected with synthetic, Arg-containing endopeptidase substrates. Purification and characterization studies showed that the enzyme was plasma kallikrein. Plasma kallikrein in association with the proteinase inhibitor alpha 2-macroglobulin was demonstrated to be a predominant form of the enzyme in the fluid, suggesting that the enzyme activity is regulated by the inhibitor. The study also indicated that the plasma kallikrein present in follicular fluid probably comes from the liver.