Intracellular localization and characterization of 3-hydroxykynureninase in human liver.
3-hydroxykynureninase in human liver was present in cytosol and mitochondria. The cytosolic enzyme and mitochondrial enzyme had the same physiological and enzymic properties. The enzyme had a mol. wt of 130,000 by gel filtration and isoelectric point of pH 5.9. The enzyme was active for 3-hydroxykynurenine and kynurenine, and its activity ratio was 15:1. The apparent Km values of the enzyme were 7.7 X 10(-5) M for 3-hydroxykynurenine, 1.0 X 10(-3) M for kynurenine and 2.5 X 10(-6) M for pyridoxal 5'-phosphate with 3-hydroxykynurenine. Some other properties of purified enzymes are described.
D000368:Aged; D003600:Cytosol / Q000201:enzymology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006867:Hydrolases / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008297:Male; D008930:Mitochondria, Liver / Q000201:enzymology; D011732:Pyridoxal Phosphate / Q000494:pharmacology
D011732:Pyridoxal Phosphate; D006867:Hydrolases; C021400:3-hydroxykynureninase