Ishimitsu S, Fujimoto S, Ohara A
Kyoto Pharmaceutical University, Japan.
Chem Pharm Bull (Tokyo). 1990 May;38(5):1417-8. doi: 10.1248/cpb.38.1417.
When phenylalanine was irradiated at ultraviolet (UV) light, p-tyrosine, m-tyrosine and o-tyrosine were identified as hydroxylated products. From p-tyrosine and m-tyrosine, the formation of L-3,4-dihydroxyphenylalanine (DOPA) was observed. The hydroxylation of phenylalanine was prevented by radical scavengers, e.g., catalase, superoxide dismutase, sodium thiocyanate, mannitol, potassium iodide and thiourea. Replacement of air with nitrogen gas prevented the hydroxylation, but did not depress it completely. The addition of H2O2 increased significantly the hydroxylation of phenylalanine. These results suggest that the hydroxylation of phenylalanine by UV irradiation may be caused by .OH formed during the decomposition of H2O.
当苯丙氨酸受到紫外线（UV）照射时，对酪氨酸、间酪氨酸和邻酪氨酸被鉴定为羟基化产物。从对酪氨酸和间酪氨酸中，观察到了L-3,4-二羟基苯丙氨酸（多巴）的形成。自由基清除剂，如过氧化氢酶、超氧化物歧化酶、硫氰酸钠、甘露醇、碘化钾和硫脲，可阻止苯丙氨酸的羟基化。用氮气代替空气可阻止羟基化，但不能完全抑制它。添加过氧化氢可显著增加苯丙氨酸的羟基化。这些结果表明，紫外线照射引起的苯丙氨酸羟基化可能是由H2O分解过程中形成的·OH所致。
