[DNP-peptidase activity in the rabbit ovary (author's transl)]

To examine the possible roles of collagenolytic enzymes in the follicular wall at ovulation, we measured in rabbit ovaries collagenolytic enzymes by using synthetic substrates, DNP-Pro-Gln-Gly-Ile-Ala-Gly-Gln-D-Arg OH supposed to be specific for vertebrate collagenase. Our results clearly demonstrated that DNP-peptidase activity existed, with its optimal pH7.6-pH7.8 in rabbit ovarian follicles. DNP-peptidase activity steadily increased for nine hours following the hCG injection. After nine hours of enzyme activity decreased sharply until about the tenth hour, at which time ovulation had occurred. This pattern of enzyme activities indicates that the DNP-peptidase was consumed for degradation of collagen fibers. After collagen fibers have been completely degraded, this enzyme was increased again. These changes of DNP-peptidase activities at ovulation were similar to cathepsin B1 activities with its optimal pH6.0. It is concluded that DNP-peptidase could be one of ovulatory enzymes in the rabbit.