Specificity of a human leukocyte neutral proteinase with bovine parathyroid hormone as substrate.

A neutral proteinase, located on the surface of human granulocytes and lymphocytes, degraded bovine parathyroid hormone in vitro. The observed sites of cleavage were between residues 5 and 6 (--ile--gln--), 8 and 9 (--met--his--), 38 and 39 (--gly--ala--) and 41 and 42 (--ile--ala--). Possible physiological implications of these findings are discussed.