Purification and characterization of D-3-aminoisobutyrate-pyruvate aminotransferase from rat liver.
D-3-Aminoisobutyrate-pyruvate aminotransferase (EC 2.6.1.40) was purified 1900-fold from rat liver extract. The purified enzyme showed a molecular mass of 180 kDa by gel-permeation HPLC analysis using a TSK gel G3000SW column. Reductive polyacrylamide gel electrophoresis in sodium dodecyl sulfate resulted in identification of a single band of approx. 50 kDa, indicating that the native enzyme is probably a tetrametric protein. The specific activity of the purified enzyme was 1.14 mumol/min per mg protein. D-3-Aminoisobutyrate and beta-alanine were good amino donors. The Km value for L-3-aminoisobutyrate was 100-times larger than that for the D-isomer. The apparent Km values for D-3-aminoisobutyrate and beta-alanine were 35 and 282 microM, respectively. Pyruvate, glyoxylate, oxalacetate, 2-oxo-n-valerate, and 2-oxo-n-butyrate were good amino acceptors. The apparent Km values for pyruvate and glyoxylate were 32 and 44 microM, respectively.
Ueno
S
S
Department of Neuropsychiatry, Ehime University School of Medicine, Japan.
Morino
H
H
Sano
A
A
Kakimoto
Y
Y
D000818:Animals; D002384:Catalysis; D002851:Chromatography, High Pressure Liquid; D002853:Chromatography, Liquid; D002855:Chromatography, Thin Layer; D004591:Electrophoresis, Polyacrylamide Gel; D007526:Isoelectric Point; D008099:Liver / Q000201:enzymology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013056:Spectrophotometry, Ultraviolet; D013379:Substrate Specificity; D000637:Transaminases / Q000032:analysis / Q000302:isolation & purification*
D000637:Transaminases; C019685:D-3-aminoisobutyrate-pyruvate aminotransferase