色氨酸对黑素体酪氨酸酶催化多巴氧化的影响。

The effect of tryptophan on dopa-oxidation by melanosomal tyrosinase.

Chakraborty A K, Chakraborty D P

Department of Dermatology, Kobe University School of Medicine, Japan.

Int J Biochem. 1993 Sep;25(9):1277-80. doi: 10.1016/0020-711x(93)90079-t.

Abstract

Tryptophan has been shown to inhibit dopa-oxidation by melanosomal tyrosinase. 2. The inhibition is of mixed-type with Ki = 1.6 x 10(-3) M. 3. Tryptophan does not interact with the oxidation product of the dopa-oxidase reaction. 4. Neither oxygen nor hydroxyl radicals are involved in the inhibition found in presence of tryptophan. 5. Tryptophan, like dopa, also inhibits tyrosine hydroxylase and dopa-oxidase activity of melanosomal tyrosinase and its inhibitory mechanism differs from inhibition due to non-substrate type compounds like cysteine, ascorbic acid. 6. These experiments together with previous findings suggest that the status of tryptophan may be similar to that of dopa in relation to regulation of melanogenesis.

摘要

色氨酸已被证明可抑制黑素体酪氨酸酶的多巴氧化。2. 这种抑制作用为混合型，抑制常数Ki = 1.6×10⁻³ M。3. 色氨酸不与多巴氧化酶反应的氧化产物相互作用。4. 色氨酸存在时所发现的抑制作用既不涉及氧气也不涉及羟基自由基。5. 色氨酸与多巴一样，也抑制黑素体酪氨酸酶的酪氨酸羟化酶和多巴氧化酶活性，其抑制机制不同于半胱氨酸、抗坏血酸等非底物类型化合物所引起的抑制。6. 这些实验与先前的研究结果共同表明，在黑素生成的调节方面，色氨酸的状态可能与多巴相似。