Abstract
Summary
Several peptidyl hydrolases with known specificity were tested for their capacity to inactivate the melanocyte-stimulating hormone-release-inhibiting factor (MSH-R-IF). Leucineaminopeptidase, aminopeptidase M, thermolysin, and brain arylamidase degraded this inhibiting hormone, but collagenase, the carboxypeptidases A and B, and chymotrypsin did not. Crude rat tissue extracts were also tested for enzymic activity. Brain extracts were highly active in degrading MSH-R-IF, whereas extracts of the median eminence, a storage site for the factor, were significantly less active.
The authors are grateful to Mrs. H. Shlank for excellent technical assistance.
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