A transminase acting on cystathionine, S-aminoethylcysteine and glutamine has been purified to homogeneity from bovine brain by ammonium sulfate precipitation. DE-52 chromatography, octyl-Sepharose chromatography, hydroxylapatite chromatography and gel filtration. The enzyme was purified 4700 times over the bovine brain homogenate and the overall recovery of the enzyme activity was about 18%. As demonstrated by polyacrylamide gel electrophoresis under native or denaturing conditions, the enzyme has a molecular mass of 100 kDa and is composed of two subunits with approximately identical weight. A single active peak was obtained at pH = 5.24 by chromatofocusing of a homogeneous enzyme preparation. K(m) values for S-aminoethylcysteine have been calculated using various ?-keto acids as amino acceptor and K(m) for glutamine has been determined with ?-keto-?-methiolbutyric acid as cosubstrate. The occurrence of the enzyme activity in some bovine brain regions was also studied.
S-Aminoethyl-L-cysteine transaminase from bovine brain: purification to homogeneity and assay of activity in different regions of the brain / Pensa, Bernardo; Achilli, Marco; Fontana, Mario; Caccuri, Am; Cavallini, Doriano. - In: NEUROCHEMISTRY INTERNATIONAL. - ISSN 0197-0186. - STAMPA. - 15:(1989), pp. 285-291. [10.1016/0197-0186(89)90134-4]
S-Aminoethyl-L-cysteine transaminase from bovine brain: purification to homogeneity and assay of activity in different regions of the brain.
PENSA, Bernardo;ACHILLI, Marco;FONTANA, Mario;CAVALLINI, Doriano
1989
Abstract
A transminase acting on cystathionine, S-aminoethylcysteine and glutamine has been purified to homogeneity from bovine brain by ammonium sulfate precipitation. DE-52 chromatography, octyl-Sepharose chromatography, hydroxylapatite chromatography and gel filtration. The enzyme was purified 4700 times over the bovine brain homogenate and the overall recovery of the enzyme activity was about 18%. As demonstrated by polyacrylamide gel electrophoresis under native or denaturing conditions, the enzyme has a molecular mass of 100 kDa and is composed of two subunits with approximately identical weight. A single active peak was obtained at pH = 5.24 by chromatofocusing of a homogeneous enzyme preparation. K(m) values for S-aminoethylcysteine have been calculated using various ?-keto acids as amino acceptor and K(m) for glutamine has been determined with ?-keto-?-methiolbutyric acid as cosubstrate. The occurrence of the enzyme activity in some bovine brain regions was also studied.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
