Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.11.18 (MAP)
 7,412 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Aminopeptidases (EC.3.4.11...) are widely distributed in nature and have medical and biological importance due to their function in the modification and degradation of protein. Two aminopeptidases were purified from rabbit kidney homogenate by ion exchange and gel filtration chromatography columns, using aminoacyl of beta-naphthylamides and p-nitroanilides as substrates. The enzymes' homogeneity was assured by SDS-PAGE. The first enzyme (P1) has an optimum of pH 7.0, a molecular mass of 70 kDa, best catalytical efficiency for methionyl-beta-naphthylamide, is 70% inhibited by 0.5 mM Zn2+ and Co2+ ions, 3.33 mM sodium hydrocortisone succinate and 0.08 mM p-hydroxymercuribenzoate, and is little or not inhibited by EDTA, amino acids, p-nitroaniline, beta-naphthylamine, deoxicholate, bestatin and puromycin. The second enzyme (P2) has an optimum of pH 7.0, a molecular mass of 54 kDa, best catalytical efficiency for Leu-beta-naphthylamide, is inhibited by 0.5 mM ions Zn2+ (45%), 0.02 mM EDTA (94%) 0.08 mM p-hydroxymercuribenzoate (70%), 3.33 mM beta-ME (13%), 1.33 mM p-nitroaniline (40%), 1.33 mM beta-naphthylamine (17%), 1.33 mM sodium deoxicholate (96%), 3.33 mM sodium hydrocortisone succinate (60%), and is 30% activated by 0.5 mM Co2+ ions. Puromycin and bestatin are competitive inhibitors with Ki values in 10(-6) and 10(-7) M order, respectively. P1 is a methionine aminopeptidase, while P2 is a leucine aminopeptidase.
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PMID:Rabbit kidney aminopeptidases: purification and some properties. 1061 14

Puromycin is an experimental anti-tumor antibiotic acting through inhibition of protein synthesis. Because of its untoward side effects (as inner ear and renal lesions) the antibiotic was not approved for clinical trials. The mechanism underlying the organ specificity of the side effect is not understood. In view of the fact that a number of drugs form with melanin complexes that affect their pharmacological activity, we determined whether puromycin interacts with melanin and how this process affects biosynthesis of collagen in cultured human skin fibroblasts. Our results indicate that puromycin forms complexes with melanin. The amount of puromycin bound to melanin increases with increase of initial drug concentration. The Scatchard plot analysis of the drug binding to melanin has shown that at least two classes of independent binding sites are implicated in the puromycin-melanin complex formation: one class of strong binding sites with the association constant K1 = 1.84 x 10(6) M(-1), and the second class of weak binding sites with the association constant K2 = 5.26 x 10(3) M(-1). The number of total binding sites were n1 = 0.1260 and n2 = 0.2861 mumol puromycin per 1 mg melanin. We found that puromycin induced inhibition of collagen and DNA biosynthesis (IC50 approximately 2 microM). Melanin at 100 microg/ml produced about 20% inhibition of DNA synthesis, but it had no effect on collagen biosynthesis in cultured fibroblasts. However, the addition of melanin (100 microg/ml) to puromycin - treated cells (2 microM) abolished the inhibitory action of puromycin on collagen and DNA biosynthesis. We have suggested that IGF-I receptor expression, involved in collagen metabolism, may be one of the targets for puromycin - induced inhibition of collagen biosynthesis. It was found that melanin abolished puromycin induced decrease in the expression of IGF-I receptor as well MAP kinases expression: ERK1 and ERK2 as shown by Western immunoblot analysis. These data suggest that tissue specific pharmacological activity of puromycin may depend on the melanin abundance in tissues.
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PMID:Melanin counter act puromycin-induced inhibition of collagen and DNA biosynthesis in human skin fibroblasts. 1590 70