title: Organ distribution, purification and characterization of kynureninase in Suncus murinus (Insectivora) and anthranilic acid level in the serum.
abstract: 1. The highest kynureninase activity was measured in Suncus liver compared with other organs tested. The holo-enzyme activity detected in liver was 25%. 2. The enzyme mainly localized in liver cytosol was purified to a single protein band by heat treatment, ammonium sulfate fractionation, DEAE-sepharose, hydroxyapatite and phenyl-sepharose column chromatography. 3. The purified enzyme was effective for both kynurenine and 3-hydroxykynurenine, and showed the optimum pH at 8.5 against both substrates. 4. Km values were 250 microM, 18 microM and 70 microM for kynurenine, 3-hydroxykynurenine and pyridoxal 5'-phosphate, respectively. Various compounds such as histidine, aspartate and nicotinamide enhanced the enzyme activities. 5. Anthranilate, the product of kynureninase, was present at a concentration in Suncus serum of 1.96 microM. This value was higher than those of rat and human.
authors.affiliation: Department of Biochemistry, Wakayama Medical College, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Ishikawa
authors.forename: E
authors.initials: E
authors.lastname: Okuno
authors.forename: J
authors.initials: J
authors.lastname: Kawai
authors.forename: R
authors.initials: R
authors.lastname: Kido
mesh_terms: D000818:Animals; D006863:Hydrogen-Ion Concentration; D006867:Hydrolases / Q000302:isolation & purification / Q000378:metabolism*; D007526:Isoelectric Point; D007700:Kinetics; D008099:Liver / Q000201:enzymology; D008297:Male; D008970:Molecular Weight; D012788:Shrews / Q000378:metabolism*; D014018:Tissue Distribution; D062367:ortho-Aminobenzoates / Q000097:blood*
chemical_list: D062367:ortho-Aminobenzoates; C031385:anthranilic acid; D006867:Hydrolases; C021480:kynureninase