A chloride activated alanine aminopeptidase from a melanoma cell line.
Alanine aminopeptidase was partially purified from cultured human melanoma cells (Bowes) by gel filtration on Sephadex G-200 and DEAE Sepharose column chromatography. The molecular weight of the enzyme was about 52,000 as determined by gel filtration on Sephadex G-100. The enzyme hydrolyzed L-alanine beta-naphthylamide (NA), but not or slightly L-methionine-NA, L-leucine-NA, and L-arginine-NA. The Km value for L-alanine-NA was 0.17 mmol/l, pH optimum was 7.4. The enzyme was stable at 50 degrees C for 20 min, but lost about 50% of its activity at 60 degrees C within 20 min. It was markedly stimulated by chloride ions, and was inhibited by sulfhydryl blocking agents and EDTA. The activity was restored by the addition of Co2+ or Zn2+ after EDTA treatment. The enzyme is a metallo- and thiol-dependent and chloride-activated, low-molecular weight aminopeptidase.
Tsushima
H
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Department of Physiology, Miyazaki Medical College, Japan.
Hopsu-Havu
V K
VK
D000626:Aminopeptidases / Q000032:analysis*; D018826:CD13 Antigens; D002712:Chlorides / Q000494:pharmacology*; D004492:Edetic Acid / Q000494:pharmacology; D006801:Humans; D008545:Melanoma / Q000201:enzymology*; D008970:Molecular Weight; D013379:Substrate Specificity; D013438:Sulfhydryl Compounds / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D002712:Chlorides; D013438:Sulfhydryl Compounds; D004492:Edetic Acid; D000626:Aminopeptidases; D018826:CD13 Antigens