| Autor: |
Phillips RS; Department of Chemistry, School of Chemical Sciences, University of Georgia, Athens 30602., Fletcher JG, Von Tersch RL, Kirk KL |
| Jazyk: |
angličtina |
| Zdroj: |
Archives of biochemistry and biophysics [Arch Biochem Biophys] 1990 Jan; Vol. 276 (1), pp. 65-9. |
| DOI: |
10.1016/0003-9861(90)90010-v |
| Abstrakt: |
The reactions of 2-fluoro- and 3-fluoro-L-tyrosine with mushroom tyrosinase have been investigated. Both fluorinated tyrosines are good substrates for tyrosinase, with Vmax and Vmax/Km values similar to those for L-tyrosine. Oxygenation of 2-fluorotyrosine is regioselective, and only 6-fluorodopa was detected by HPLC in reaction mixtures. Oxygenation of both isomers of monofluorotyrosine results in fluoride ion production in the absence of ascorbic acid; however, 2-fluorotyrosine also produces fluoride in the presence of ascorbic acid. These results are consistent with previous studies demonstrating rapid intramolecular cyclization of nascent 6-fluorodopaquinone (M.E. Rice, B. Moghaddan, C.R. Creveling, and K.L. Kirk, 1987, Anal. Chem. 59, 1534-1538), which is competitive with reduction by ascorbate, resulting in elimination of the aromatic fluorine as fluoride ion. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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