Thiosulphate esters in keratin attacked by dermatophytesin vitro

A strong basophilia was demonstrated in human hair attacked, in vitro, by Microsporum gypseum. With model substrates e.g. chemically modified keratins, histochemical studies showed that in the regions attacked, S-thiosulphate esters were present apart from the carboxyls originating by proteolysis of peptide chains. Such groups arise from cleavage of cystine bonds by sulphite. Previous personal work showed that sulphite was produced during growth of the fungus on a cystine-containing medium and it is assumed that the denaturation of keratin by sulphitolysis could be a key reaction in keratin decomposition by dermatophytes.