Beta-alanine and tanning polymorphisms

1. Beta-alanine is found in mycelial walls of mature tan, but not immature white, stage of Morchella esulenta, nor in any stage of a permanently white mutant. 2. Beta-alanine is also found in hydrolysed water-extracts of human hair, the concentration being higher in blond than in dark brown, and in pigmented than in unpigmented hair. 3. Beta-alanine, added to tyrosinase-oxidized tyrosine, dopa, or dopamine has only a slight yellowing influence on the final black pigment; but when the amino group of tyrosine is combined with leucine, added beta-alanine produces stable tan pigments. 4. With L-alanine substituted for beta-alanine in this reaction, green pigment results. 5. Gelatin filters stained with the tan pigment allow solar heating of underlaying water more quickly than do those stained with the black pigment. Unstained filters allow such heating even more quickly. 6. Beta-alanine enhances production of tan pigment when heated with the phospholipid, lecithin. Implications for pigmentary adaptation, and formation of lipofuscin-like age pigments are discussed.