The metabolism of neuropeptides. Both phosphoramidon-sensitive and captopril-sensitive metallopeptidases are present in the electric organ of Torpedo marmorata.
A membrane fraction from the electric organ of Torpedo marmorata hydrolyses the Gly3-Phe4 bond of [D-Ala2, Leu5]enkephalin as well as the Gly-His bond of benzoyl-Gly-His-Leu. The hydrolysis of benzoyl-Gly-His-Leu is completely inhibitable by Captopril (I50 = 19nM), consistent with peptidyl dipeptidase activity, but enkephalin hydrolysis is inhibited to a maximum of only 70%. The residual activity hydrolysing enkephalin is inhibited by phosphoramidon (I50 = 15nM) and therefore resembles endopeptidase-24.11, a mammalian plasma-membrane enzyme implicated in the metabolism of neuropeptides. Both enkephalin-hydrolysing activities in Torpedo electric organ are inhibited by 1,10-phenanthroline, like their mammalian counterparts. The peptidases may function in the hydrolysis of endogenous peptides or in neurotransmitter exocytosis in the electric organ.
D000818:Animals; D002216:Captopril / Q000494:pharmacology; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology; D004557:Electric Organ / Q000187:drug effects / Q000201:enzymology*; D010450:Endopeptidases / Q000378:metabolism*; D004743:Enkephalin, Leucine / Q000031:analogs & derivatives / Q000378:metabolism; D016308:Enkephalin, Leucine-2-Alanine; D006020:Glycopeptides / Q000494:pharmacology; D006868:Hydrolysis; D066298:In Vitro Techniques; D008666:Metalloendopeptidases; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009842:Oligopeptides / Q000378:metabolism; D010618:Phenanthrolines / Q000494:pharmacology; D014101:Torpedo / Q000378:metabolism*
D006020:Glycopeptides; D009419:Nerve Tissue Proteins; D009842:Oligopeptides; D010618:Phenanthrolines; C010980:hippuryl-histidyl-leucine; D004743:Enkephalin, Leucine; D016308:Enkephalin, Leucine-2-Alanine; D002216:Captopril; D010450:Endopeptidases; D008666:Metalloendopeptidases; C008890:phosphoramidon; C025205:1,10-phenanthroline