Production of Pigments Similar to Those from Hair from Amino Acid and Keratin Interaction

On the Composition of Feather Extracts Used in Allergy Practice

“…The absorption spectrum of the deep red compound in 6 n HC1 had a shoulder at 360 nm, a minor peak at 490 nm and a sharp maximum at 550 nm; minima lay at 445 and 510 nm. The red substance probably is identical to the compound described in hydrolysates of red hair and feathers by Hanna [19], Barnicot [2] and termed trichosiderin by Flesch [16,17]; the nature of the compound is unknown but the results of Hanna indicate it to be an inter action product of tryptophan (or one of its derivatives) with another keratin constituent, presumably a sulphur-containing amino acid. (c) Optical Analysis Feather allergens are deepbrown in neutral or alkaline solution; the colour reversibly changes to pale brown or yellow in acid media, a phenomenon also observed with other inhalant allergens and already evaluated elsewhere [5].…”