| 摘要 |
A chorionic peptidase-1 (C-ase-1) which is isolated from human placenta that inactivates the immunoreactivity of GnRH, TRH and angiotension II. Only in the presence of dithiothreitol (DDT), a sulfhydryl agent, are oxytocin and somatostatin inactivated by this peptidase. However, C-ase-1 is without effect on CRF, hCS or hCG. C-ase-1 also inhibits the biological activity of GnRH, i.e. its ability to stimulate pituitary LH and FSH. The ability of this peptidase to inactivate GnRH, TRH and angiotension II can be inhibited by various peptidase inhibitors. These peptidase inhibitors include bacitracin, para-amino bensamidine, DMSO and diisopropylfluorophosphate. The activity of C-ase-1 in GnRH has also been demonstrated to be a post-proline peptidase. Isolation of this protein, C-ase-1, has been effected using permeation, ion exchange and affinity chromatography and HPLC. As estimated by SDS-PAGE and HPLC analysis, C-ase-1 has an apparent molecular weight of about 58,000 daltons. It is proposed that C-ase-1 may be an important chorionic regulator of GnRH, TRH and angiotension II levels during pregnancy.
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