Purificação e caracterização parcial de ATPase de encéfalo de rata

Abstract

In this work, a rat brain ATPase was purified and partially characterized using DEAE-Sepharose and phosphocellulose columns. The brains were homogenized in Imidazole Buffer pH 8.0 and centrifuged, at 4ºC, at 38,900 g X 40 minutes. The supernatant was applied to a DEAE-Sepharose column and to the collected Flow Through powder ammonium sulfate was added until it reached 35% saturation. After centrifugation, the supernatant obtained is applied to a phosphocellulose column centrifugation, the obtained supernatant is applied to a phosphocellulose column at pH 6.8 and retained proteins were eluted changing the pH to 8.0. The fractions eluted from this column have polypeptides of lower molecular weight between 50 and 60 kDa. The fraction enriched in ATPásica activity has the following characteristics: 1) In the concentration of 1.0 mM of substrate the ATPásica activity is 2.5 times greater than the GTPásica activity; 2) MgATPásica activity is 20 times greater than CaATPásica activity and is not sensitive to Ca ++ and Ca ++ / CaM; 3) There was no actin stimulation and no K-EDTA ATPasic activity was detected; 4) It is inhibited in the presence of high concentrations of salts (NaCI, KCI and 0.3M KI), aluminum fluoride and 0.2% Triton X 100; 5) It is not inhibited by azide and vanadate; 6) The activity is higher in acidic pH (pH 5.0).