Microbial metabolism of quinoline and related compounds. XVI. Quinaldine oxidoreductase from Arthrobacter spec. Rü 61a: a molybdenum-containing enzyme catalysing the hydroxylation at C-4 of the heterocycle.
Quinaldine oxidoreductase from Arthrobacter spec. Rü 61a converts quinaldine to 1H-4-oxoquinaldine. The enzyme was purified 70-fold to apparent homogeneity in a 5-step procedure with a recovery of 4%. The molecular mass of the native enzyme was calculated to be 340,000 Da by gel filtration. SDS-polyacrylamide gel electrophoresis of the enzyme revealed 3 protein bands corresponding to 82,000 Da, 35,000 Da and 22,000 Da. The enzyme contained 1.6 atoms of molybdenum, 8 atoms of iron, 8 atoms of acid labile sulfur, 2 molecules of FAD and as part of the molybdenum cofactor, molybdopterin cytosine dinucleotide. Due to the composition of the cofactors the quinaldine oxidoreductase belongs to the class of molybdo-iron/sulfur-flavoproteins. Cyanide, arsenite and 4-hydroxymercuribenzoate were effective inhibitors whereas the enzyme was not affected by methanol.
de Beyer
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A
Institut für Mikrobiologie, Universität Hohenheim.
Lingens
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F
D000595:Amino Acid Sequence; D001173:Arthrobacter / Q000201:enzymology*; D002850:Chromatography, Gel; D003067:Coenzymes / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D006900:Hydroxylation; D007501:Iron / Q000378:metabolism; D007525:Isoelectric Focusing; D008667:Metalloproteins; D008969:Molecular Sequence Data; D008970:Molecular Weight; D008982:Molybdenum / Q000378:metabolism*; D010088:Oxidoreductases / Q000032:analysis / Q000302:isolation & purification / Q000378:metabolism*; D011804:Quinolines / Q000378:metabolism*; D013056:Spectrophotometry, Ultraviolet; D013379:Substrate Specificity
D003067:Coenzymes; D008667:Metalloproteins; D011804:Quinolines; D008982:Molybdenum; D007501:Iron; D010088:Oxidoreductases; C080754:quinaldine oxidoreductase