Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01178 (oxytocin)
 15,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human placental aminopeptidase M and A and post-proline endopeptidase are known to act as degrading enzymes of bioactive peptides such as angiotensin II, oxytocin and endogenous opioids. We tested the effects of cortisol on the activities of human placental aminopeptidase A and M and post-proline endopeptidase using short-cultured placental tissues. From 34.5 nM to 3.45 microM of cortisol significantly increased the activities of 3 enzymes. Our present data suggest a possible important role of cortisol in the growth of human placenta via induction of placental aminopeptidases.
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PMID:Induction by cortisol of aminopeptidases production from the human placenta in tissue culture. 134 55

The hydrolysis of oxytocin by human placental subcellular fractions was studied in the presence of selective inhibitors by measuring liberated amino acids by high performance liquid chromatography (HPLC). Oxytocin degradation by microsomal and lysosomal fractions was inhibited by bestatin, amastatin and puromycin. The IC50 values of these inhibitors on oxytocin degradation by both fractions were similar to those of these inhibitors on the human placental aminopeptidase M measured by L-Leu-p-nitroanilide as a substrate (LAP activity), which we reported previously. However, purified aminopeptidase M from human placental microsomal fractions could not liberate any amino acid from oxytocin. Since phosphoramidon (1 mumol/l), a putative metalloendopeptidase inhibitor, and N-benzylcarbonyl-valyl-prolinal (Z-Val-prolinal) (14 mumol/l), a selective inhibitor of post-proline endopeptidase, could not significantly influence the degradation of oxytocin by either subcellular fractions, neither enzyme seems to be actively involved in oxytocin degradation. These results strongly suggested the existence of oxytocinase(s) other than the above three enzymes in microsomal and/or lysosomal fractions of human placenta.
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PMID:Degradation of oxytocin by the human placenta: effect of selective inhibitors. 135 23

Aminopeptidase M (EC 3.4.11.2), an enzyme present on the cell surface of vascular endothelium and/or smooth muscle, rapidly hydrolyzes leucyl- and arginyl-2-naphthylamides and a number of vasoactive peptides at physiologic pH. Utilizing both thin-layer chromatography and high pressure liquid chromatography, it was found that vascular aminopeptidase M converted kallidin to bradykinin and inactivated des(Asp1)angiotensin I, angiotensin III, hepta(5-11)substance P and hexa(6-11)substance P. Aminopeptidase M did not, however, hydrolyze bradykinin, angiotensin I, angiotensin II, saralasin, vasopressin, oxytocin or any form of substance P containing a component of the Arg-Pro-Lys-Pro sequence. Both the naphthylamidase and peptidase activities were inhibited similarly by known amino-peptidase M inhibitors including o-phenanthroline, amastatin, bestatin and puromycin. However, inhibitors of angiotensin I converting enzyme (captopril), carboxypeptidase N (MERGETPA), neutral endopeptidase (phosphoramidon), post proline cleaving enzyme and dipeptidyl(amino)peptidase IV (diisopropylphosphofluoridate, DFP) were without effect. These results demonstrate that vascular, cell surface aminopeptidase M can selectively metabolize vasoactive peptides and may play a role in modulating their levels in the circulation and/or within the vessel wall.
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PMID:Vascular, plasma membrane aminopeptidase M. Metabolism of vasoactive peptides. 240 81

Vasoactive peptides contain a high proportion of proline residues which make them resistant to hydrolysis by many peptidases. However, post proline cleaving enzyme (PPCE; EC 3.4.21.26), a proline specific endopeptidase which specifically hydrolyzes internal peptide bonds on the carboxyl side of proline residues, has been shown to inactivate numerous vasoactive peptides including angiotensins, kinins, substance P, vasopressin and oxytocin. In order to determine whether PPCE could be involved in vascular metabolism of vasoactive peptides, we carried out localization and characterization studies of PPCE-like activity in hog aorta and mesenteric artery. PPCE was assayed fluorometrically at pH 7.0 using the specific PPCE substrate CBZ-Gly-Pro-4-methyl-coumarinylamide. The subcellular distribution of vascular PPCE was essentially the same as that of the cytosolic marker enzyme lactic dehydrogenase (LDH). PPCE was enriched six-fold in the cytosolic fraction (11.4 +/- 2.7 units/mg) and unlike the plasma membrane-bound proline specific exopeptidase dipeptidyl-(amino)peptidase IV (DAP IV; EC 3.4.14.5), little or no activity could be detected in the microsomal or plasma membrane fractions. Similar to PPCE characterized from other sites, vascular PPCE was stabilized and activated by dithiothreitol and EDTA, and inhibited by DFP, p-chloromercuriphenyl sulfonic acid, L-1-tosylamido-2-phenylethylchloromethyl ketone, Cu++, Ca++, and Zn++. Vascular PPCE was unaffected by inhibitors of trypsin and kallikrein (Aprotinin, ABTI), aminopeptidase M (bestatin, amastatin), neutral endopeptidase (phosphoramidon), angiotensin I converting enzyme (captopril) or carboxypeptidase N (MERGETPA). These data demonstrate that PPCE is present in vascular endothelium and/or smooth muscle.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Vascular, post proline cleaving enzyme: metabolism of vasoactive peptides. 354 18