Isolation of a new tautomerase monitored by the conversion of D-dopachrome to 5,6-dihydroxyindole.
Two membrane bound enzymes which tautomerize L-dopachrome and are specific for the L-isomer of dopachrome have been defined in melanin forming cells. Another enzyme that tautomerizes D-dopachrome with concomitant decarboxylation to give 5,6-dihydroxyindole (DHI) was found in the cytoplasm of human melanoma cells, human liver and in all of the organs studied in rat. The decolorization of D-dopachrome with the formation of DHI was used in monitoring the isolation of a tautomerase from liver of male rats and therefore the enzyme is provisionally called D-dopachrome tautomerase. The molecular weight of D-dopachrome tautomerase monomer was approximately 12 kD and its N-terminal amino acid sequence was P-F-V-E-L-E-T-N-L-P-A-. The Km for D-dopachrome was 1.5 mM and Vmax 0.5 mmol per min and mg protein.
Odh
G
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Department of Pharmacology, University of Lund, Sweden.
Hindemith
A
A
Rosengren
A M
AM
Rosengren
E
E
Rorsman
H
H
D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000201:enzymology; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D045563:Indolequinones; D007211:Indoles / Q000032:analysis / Q000378:metabolism*; D019746:Intramolecular Oxidoreductases; D007535:Isomerases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D007668:Kidney / Q000201:enzymology; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008297:Male; D008545:Melanoma; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009206:Myocardium / Q000201:enzymology; D010446:Peptide Fragments / Q000737:chemistry; D011809:Quinones / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017386:Sequence Homology, Amino Acid; D013154:Spleen / Q000201:enzymology; D014407:Tumor Cells, Cultured
D045563:Indolequinones; D007211:Indoles; D010446:Peptide Fragments; D011809:Quinones; C001123:dopachrome; D007535:Isomerases; D019746:Intramolecular Oxidoreductases; C042501:dopachrome isomerase; C033871:5,6-dihydroxyindole