CLONING AND FUNCTIONAL EXPRESSION OF HUMAN KYNURENINE 3-MONOOXYGENASE

Kynurenine 3-monooxygenase, an NADPH-dependent flavin monooxygenase, c atalyses the hydroxylation of L- kynurenine to L-3-hydroxykynurenine. By hybridization screening using a cDNA probe encoding the entire exon 2 of Drosophila melanogaster kynurenine 3-monooxygenase, we isolated a 2.0 kb cDNA clone coding for the corresponding human liver enzyme. T he deduced amino acid sequence of the human protein consists of 486 am ino acids with a predicted molecular mass of 55 762 Da, Transfection o f the human cDNA in HEK-293 cells resulted in the functional expressio n of the enzyme,vith kinetic properties similar to those found for the native human protein, RNA blot analysis of human tissues revealed the presence of a major mRNA species of similar to 2.0 kb in liver, place nta and kidney. (C) 1997 Federation of European Biochemical Societies.