Menter J M, Willis I
J Invest Dermatol. 1980 Sep;75(3):257-60. doi: 10.1111/1523-1747.ep12523286.
The interaction between the skin depigmenter 4-tert-butylcatechol (tBC) and L-DOPA melanin was qualitatively studied by means of spectroscopically monitoring the binding of tBC melanin as well as the oxidation of tBC in the presence and absence of melanin. Additionally, we assessed the quantitative effect of tBC on melanin's chemical reactivity by using the reduction of potassium ferricyanide as a redox marker. The kinetics of ferricyanide reduction in the ternary (melanin/tBC/ferricyanide) system are essentially different from those in each of the binary components (i.e., melanin/ferricyanide and tBC/ferricyanide). The experiments indicate that tBC can bind to melanin (KB = 3.8 X 10(3) M-1) and that melanin can act as a "catalyst-like" electron transfer agent which couples ferricyanide reduction with tBC oxidation (k' = 1.3 X 10(-6) mole min-1). These kinetic and thermodynamic parameters may provide a means of quantitatively comparing melanins obtained from different biological and pathological situations, and they may make possible an understanding of cutaneous depigmentation processes on the molecular level.
通过光谱监测4-叔丁基邻苯二酚（tBC）与黑色素的结合以及在有和没有黑色素存在的情况下tBC的氧化，对皮肤色素脱失剂4-叔丁基邻苯二酚（tBC）与L-多巴黑色素之间的相互作用进行了定性研究。此外，我们以铁氰化钾的还原作为氧化还原标记，评估了tBC对黑色素化学反应性的定量影响。三元体系（黑色素/tBC/铁氰化钾）中铁氰化钾还原的动力学与二元体系（即黑色素/铁氰化钾和tBC/铁氰化钾）中各自的动力学基本不同。实验表明，tBC可以与黑色素结合（平衡常数KB = 3.8×10³ M⁻¹），并且黑色素可以作为一种“类催化剂”电子转移剂，将铁氰化钾的还原与tBC的氧化偶联起来（反应速率常数k' = 1.3×10⁻⁶ 摩尔·分钟⁻¹）。这些动力学和热力学参数可能提供一种定量比较从不同生物学和病理学情况获得的黑色素的方法，并且可能使在分子水平上理解皮肤色素脱失过程成为可能。
