Partial purification and properties of frog liver tyrosine aminotransferase.
Hepatic tyrosine aminotransferase of the frog Rana temporaria was partially purified by (NH4)2SO4 fractionation and successive chromatography on DEAE-cellulose DE-52, Ultrogel AcA-34, DEAE-cellulose DE-52 again and, finally, hydroxyapatite. During the last step, the enzyme activity separated into two fractions; traces of a third fraction were also found. The major form was purified 6000-fold to a specific activity of 200 units/mg of protein; it was about 50% pure by electrophoretic criteria. It had mol.wt. about 85 000 as determined by gel filtration on a Sephadex G-100 column. It was not activated by added pyridoxal 5'-phosphate. The enzyme was, however, inactivated by the pyridoxal phosphate reactants canaline and amino-oxyacetate. The enzyme was specific for 2-oxoglutarate as the amino group acceptor. Homogentisate inhibited the enzyme and adrenaline was an activator; both effects were seen at low concentrations of the effectors. The relationship between initial rate and tyrosine or 2-oxoglutarate concentration was abnormal and complex. Form-2 enzyme had similar or identical molecular weight, cofactor requirements, oxo acid specificity and kinetics.
D000625:Aminooxyacetic Acid / Q000494:pharmacology; D000818:Animals; D001001:Anura; D055598:Chemical Phenomena; D002621:Chemistry; D002848:Chromatography, DEAE-Cellulose; D004837:Epinephrine / Q000494:pharmacology; D005260:Female; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008297:Male; D011896:Rana temporaria; D014443:Tyrosine / Q000031:analogs & derivatives; D014444:Tyrosine Transaminase / Q000037:antagonists & inhibitors / Q000302:isolation & purification*
D000625:Aminooxyacetic Acid; D014443:Tyrosine; D014444:Tyrosine Transaminase; D004837:Epinephrine