Metalloendopeptidases of the mouse kidney brush border: meprin and endopeptidase-24.11.

摘要: Two metalloendopeptidases, meprin and endopeptidase-24.11 ("24.11"), were isolated from mouse kidney membranes, their structural catalytic properties investigated. The enzymes both cross-react with antibodies prepared in rabbits against purified preparations of meprin; thus they share some immunologic determinants. Meprin 24.11 have similar subunit molecular weights 85 000 90 000, respectively, as demonstrated after sodium dodecyl sulfate polyacrylamide gel electrophoresis the presence 2-mercaptoethanol. However, under non-reducing conditions, migrates an oligomer while remains monomeric. This other data indicate that subunits are linked by disulfide bridges, whereas not covalently linked. Both endopeptidases hydrolyze insulin B chain totally inhibited EDTA o-phenanthroline. activity was low concentrations phosphoramidon (less than 2 nM), this inhibitor high 20 microM. Large proteins substrates for endopeptidase-24.11, degrades such azocasein rapidly (apparent Km = 0.65 mg/ml). appears to require extended polypeptide prefers smaller peptides substrates. a preference peptide bonds contain hydrophobic amino acids. With octapeptide angiotensin II substrate, central Tyr-Ile bond; also cleaves at Arg-Val Ile-His. two show many similarities immunologically, structurally catalytically, however, display distinct characteristics which may be physiologically important.