THE PRESENCE OF PHOTOREACTIVE β‐CARBOLINE FLUOROPHORES IN WEATHERED WOOL KERATIN

Solvent‐cleaned Merino wool, which was enzymatically digested with protease K, displayed a fluorescence maximum at 500 nm when excited at 430 nm. The yield of this emission was approximately 15 times greater for a fiber tips digest than for a digest of the mid‐length region of the same fibers. Separation of the components in the wool tip digest by silica gel thin‐layer chromatography revealed the presence of several fluorescent species. The chromatographic mobility of these species was similar to the behavior observed in a preparation of authentic 1‐methyltetrahydro‐P‐carboline, 1,3‐dicarboxylic acid. Mass spectroscopy of the fluorescent compounds in the wool tip digest displayed molecular ions, [M + H]+ with m/z = 273.0890 and 257.0560, and molecular weights that define the formulae C14H12N2O4 and C11H8O4N2, respectively, which correspond to β‐carboline 1,3‐dicarboxylic acids. Mass spectral evidence also indicates the presence of two other β‐carbolines.