Purification and some properties of L-alanine:4,5-dioxovaleric acid transaminase from rat liver mitochondria.
L-alanine:4,5-dioxovalerate transaminase (EC 2.6.1.44) has been purified to homogeneity from rat liver mitochondria. Molecular weight of the native enzyme is estimated to be 230,000 +/- 3000 by gel filtration. Under denaturing condition, the dissociated enzyme has a subunit of approximately 41,000 +/- 2000, indicating the enzyme apparently is composed of six identical subunits. The enzyme is heat stable and has optimal activity at pH 6.9. Km values for L-alanine and 4,5-dioxovalerate are 3.3 X 10(-3) M and 2.8 X 10(-4) M respectively. Excess dioxovalerate inhibits the enzyme activity. Pyridoxal phosphate and dithiothreitol also inhibit the enzyme activity.
D000818:Animals; D007700:Kinetics; D046911:Macromolecular Substances; D008297:Male; D008930:Mitochondria, Liver / Q000201:enzymology*; D008970:Molecular Weight; D051381:Rats; D011919:Rats, Inbred Strains; D000637:Transaminases / Q000302:isolation & purification* / Q000378:metabolism
D046911:Macromolecular Substances; D000637:Transaminases; C019687:aminolevulinate aminotransferase