As part of an investigation of neuropeptide inactivation mechanisms, we have resolved an enzymatic activity in bovine brain which catalyzes the deamidation of thyrotropin releasing hormone (TRH) and the hydrolysis of the Pro9-Gly10-NH2 bond of luteinizing hormone releasing hormone (LH-RH) from a second LH-RH degrading activity which does not degrade TRH. The former activity is similar, if not identical to, the post-proline cleaving enzyme in kidney as it is active toward the post-proline cleaving enzyme substrate CbzGly-Pro-Leu-Gly and inhibited by CbzPro-Phe and diisopropylfluorophosphate. In addition, products derived from the degradation of TRH and LH-RH by this activity show a specific cleavage on the carboxyl side of a proline residue. The latter activity has not yet been characterized with respect to its site of cleavage of the LH-RH molecule due to the presence of other contaminating peptidases.
|Number of pages||12|
|State||Published - Jun 8 1979|
Bibliographical noteFunding Information:
This research was supported in part by Grants 1-391 from the Robert A. Welch Foundation, Houston, Texas (L.B.H.), AM 13443 from the National Institutes of Health (L.B.H.), National Science Foundation Grant BNS 78-84506 (J.F.M.) and Research Career Development Award IK04 AM 00331-01 from the National Institutes of Health (J.F.M.). We are indebted to Dr. Roderich Walter for many helpful discussions during the course of these studies and for communicating to us information prior to its publication. We also wish to thank Drs. M. Soodak and J. T. Neary for providing us with the details of their assay for TRF degradation prior to its publication, and to Drs. J. Rivier and D. Freer for many helpful discussions. The technical assistance of Ms. Martha Peer and Jody Hendrick is gratefully acknowledged.
ASJC Scopus subject areas
- Neuroscience (all)
- Molecular Biology
- Clinical Neurology
- Developmental Biology