Brain arylamidase. Purfication and characterization of the soluble bovine enzyme.
1. An enzyme acting on aminoacyl-beta-naphthylamides has been isolated from the soluble fraction of bovine brain and purified 205-fold by means of ammonium sulphate fractionation, hydroxyapatite adsorption and DEAE-Sephadex column chromatography. 2. Arylamidase requires thiol groups for retention of its activity, is heat-labile and is susceptible to freezing. p-Chloromercuribenzoate and N-ethylmaleimide inactivate the enzyme rapidly. 3. Metal ions are not required for its activity, but stimulation by Mn(2+) and Mg(2+) and inactivation by Co(2+) and Zn(2+) are observed. 4. Optimum pH7.5 in phosphate buffer was exhibited for all substrates tested except l-leucyl-beta-naphthylamide, for which optimum pH is 6.5. 5. K(m) values for a number of substrates have been obtained and substrate inhibition at high concentrations was demonstrated. 6. The molecular weight is approx. 70000 as determined by Sephadex-gel filtration.
D000626:Aminopeptidases / Q000302:isolation & purification; D000818:Animals; D001921:Brain / Q000201:enzymology*; D002417:Cattle; D055598:Chemical Phenomena; D011232:Chemical Precipitation; D002621:Chemistry; D002729:Chloromercuribenzoates; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D003035:Cobalt; D004589:Electrophoresis, Disc; D005033:Ethylmaleimide; D005615:Freezing; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D006882:Hydroxyapatites; D007700:Kinetics; D008274:Magnesium; D008345:Manganese; D008722:Methods; D008970:Molecular Weight; D009281:Naphthalenes; D000644:Quaternary Ammonium Compounds; D012995:Solubility; D013438:Sulfhydryl Compounds; D015032:Zinc
D002729:Chloromercuribenzoates; D006882:Hydroxyapatites; D009281:Naphthalenes; D000644:Quaternary Ammonium Compounds; D013438:Sulfhydryl Compounds; D003035:Cobalt; D008345:Manganese; D000626:Aminopeptidases; D008274:Magnesium; D015032:Zinc; D005033:Ethylmaleimide