Purification and substrate characterization of a human enkephalin-degrading aminopeptidase.
A 5000-fold purification of the enzyme responsible for the rapid inactivation of enkephalin in human blood has been achieved: this enzyme cleaves the N-terminal tyrosine from enkephalin and from short peptides provided their first amino acid is aromatic. The enzyme, an enkephalin-degrading aminopeptidase (alpha-aminoacyl-peptide hydrolase, EC 3.4.11.11), requires a free amino group on the substrate and has a maximum activity around pH 8. Its appearance molecular weight is in the range of 80 000-90 000 and an apparent Michaelis constant of 0.4 mM was determined.
D000626:Aminopeptidases / Q000097:blood*; D002847:Chromatography, Agarose; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D004723:Endorphins / Q000097:blood*; D004745:Enkephalins / Q000097:blood*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008970:Molecular Weight; D013379:Substrate Specificity
D004723:Endorphins; D004745:Enkephalins; D000626:Aminopeptidases