Yagi M
Cancer Biochem Biophys. 1979;4(2):105-17.
Tryptophan-p-1 (trp-p-1) and p-2, which have high mutagenic and carcinogenic potential, are oxidized by catalase- and horseradish peroxidase (HRP)-H2O2 intermediates with optimum pH 5.9 (0.2 M-acetate) in catalase and pH 5.0 (0.2 M-acetate), 8.0 (0.01 M-phosphate) in HRP. The rate constants (k4) of the oxidation in the catalase at pH 5.9 (0.2 M-acetate) were 2965 M-1 x sec-1 for trp-p-1 and 576 M-1 x sec-1 for trp-p-2. In the case of HRP, 1894 M-1 x sec-1, (pH 5.0, 0.2 M-acetate) for trp-p-1 and 705 M-1 x sec-1 (pH 8.0, 0.001 M-phosphate) for trp-p-2 under each optimum condition. The oxidation products of trp-p-1 and p-2 by catalase or HRP lost completely their mutagenic potential in the mutation assay.
具有高诱变和致癌潜力的色氨酸 - p - 1（trp - p - 1）和p - 2，在过氧化氢酶以及辣根过氧化物酶（HRP） - H₂O₂体系中被氧化，在过氧化氢酶体系中最适pH为5.9（0.2M - 乙酸盐），在HRP体系中最适pH分别为5.0（0.2M - 乙酸盐）和8.0（0.01M - 磷酸盐）。在pH 5.9（0.2M - 乙酸盐）的过氧化氢酶体系中，trp - p - 1的氧化反应速率常数（k4）为2965 M⁻¹ × s⁻¹，trp - p - 2为576 M⁻¹ × s⁻¹。在HRP体系中，在各自最适条件下，trp - p - 1为1894 M⁻¹ × s⁻¹（pH 5.0，0.2M - 乙酸盐），trp - p - 2为705 M⁻¹ × s⁻¹（pH 8.0，0.001M - 磷酸盐）。trp - p - 1和p - 2在过氧化氢酶或HRP作用下的氧化产物在突变试验中完全丧失了它们的诱变潜力。
