The hydrolysis of alpha-human atrial natriuretic peptide by pig kidney microvillar membranes is initiated by endopeptidase-24.11.
alpha-Human atrial natriuretic peptide, a 28-amino-acid-residue peptide, was rapidly hydrolysed by pig kidney microvillar membranes in vitro, with a t1/2 of 8 min, comparable with the rate observed with angiotensins II and III. The products of hydrolysis were analysed by h.p.l.c., the pattern obtained with membranes being similar to that with purified endopeptidase-24.11 (EC 3.4.24.11). No hydrolysis by peptidyl dipeptidase A (angiotensin I converting enzyme, EC 3.4.15.1) was observed. The contribution of the various microvillar membrane peptidases was assessed by including specific inhibitors. Phosphoramidon, an inhibitor of endopeptidase-24.11, caused 80-100% suppression of the products. Captopril and amastatin (inhibitors of peptidyl dipeptidase A and aminopeptidases respectively) had no significant effect. Hydrolysis at an undefined site within the disulphide-linked ring occurred rapidly, followed by hydrolysis at other sites, including the Ser25--Phe26 bond.
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000378:metabolism*; D001665:Binding Sites; D002851:Chromatography, High Pressure Liquid; D010450:Endopeptidases / Q000378:metabolism*; D006868:Hydrolysis; D007668:Kidney / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D008871:Microvilli / Q000187:drug effects / Q000378:metabolism; D015260:Neprilysin; D009479:Neuropeptides / Q000378:metabolism; D007703:Peptidyl-Dipeptidase A / Q000378:metabolism; D011480:Protease Inhibitors / Q000494:pharmacology; D013552:Swine
D009479:Neuropeptides; D011480:Protease Inhibitors; D009320:Atrial Natriuretic Factor; D010450:Endopeptidases; D007703:Peptidyl-Dipeptidase A; D015260:Neprilysin