Melanogenesis Using Tyrosinate (Not Tyrosinase)

Abstract

<p>We present our initial observations regarding the effect of the presence of L-tyrosinate (= L-tyrosine disodium salt) on the auto- or Fe<sup>2+</sup>/H<sub>2</sub>O<sub>2</sub>-mediated oxidation of various catecholic substances into melanin-like pigments. We observed that L-tyrosinate inhibited the Fe<sup>2+</sup>/H<sub>2</sub>O<sub>2</sub>-mediated oxidation. In contrast, L-tyrosinate promoted the auto-oxidation of ortho-diphenols like L-DOPA, dopamine, epinephrine, norepinephrine, catechol or pyrogallol, but not a meta-diphenol like resorcinol. In addition, we briefly demonstrated the melanogenic properties of cell culture media containing L-tyrosinate. The reactions were monitored using UV-Vis spectroscopy and size exclusion chromatography. For a reaction between L-tyrosinate and L-DOPA, a large scale experiment was set up allowing us to isolate, purify and characterize using FT-IR spectroscopy the melanin-like material obtained. We discuss our observations in the context of the <i>in vitro</i> and <i>in vivo</i> study of melanogenesis and provide some directions for future research efforts.<i></i></p>

Evaluating the “Darkness” of Melanin Materials.

“…All materials, experimental conditions and collection of data were described in previous reports. [7][8][9][10][11][12][13][14][15][16][17][18] This report involves a processing of the UV-Vis spectra collected from crude reaction mixtures or from dialyzed and dried materials that were dissolved in water. Specific references and descriptions of the materials are indicated for all the results presented in this report.…”