Purification and enzymatic properties of an L-leucine aminopeptidase from swine liver.
An L-leucine aminopeptidase (alpha-aminoacyl-peptide hydrolase (cytosol), EC 3.4.11.1), having a specificity toward the substrate L-leucine amide, but not toward L-leucyl beta-naphthylamide or L-leucyl p-nitroanilide, has been purified 332-fold from swine liver, with a yield of 8.6%. This is the first purification of this enzyme from hepatic tissue. The purified enzyme submitted to analytical electrophoresis on cellulose acetate strips or in polyacrylamide gel showed a single band after straining with Ponceau S Red dye or Amido black, respectively. Purified swine liver L-leucine aminopeptidase, a cytosol enzyme, exhibited a molecular weight of 268 000 +/- 50 000 by gel filtration. It hydrolyzed L-leucine amide substrate and L-leucyl peptides. It was activated by Mg2+ and Mn2+ and inhibited by Co2+ and Zn2+. The optimum pH was 10. It was rather sensitive to heat elevation. Swine liver L-leucine aminopeptidase was inhibited by EDTA, citric acid, isocaproic acid, dodecylamine, aliphatic alcohols and p-chloromercuribenzoate but unaffected by monoiodoacetic acid and diisopropyl fluorophosphate.
D000818:Animals; D004789:Enzyme Activation / Q000187:drug effects; D006358:Hot Temperature; D007931:Leucyl Aminopeptidase / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D008099:Liver / Q000201:enzymology*; D008274:Magnesium / Q000494:pharmacology; D008345:Manganese / Q000494:pharmacology; D008970:Molecular Weight; D013379:Substrate Specificity; D013552:Swine
D008345:Manganese; D007931:Leucyl Aminopeptidase; D008274:Magnesium