Sulphitolysis in keratinolysi. Biochemical proof.

The presence of S-sulphocysteine in filtrates of the dermatophyte Keratinomyces ajelloi growing on human hair in a culture medium buffered by pH 7-4 by phosphates was demonstrated by means of ion exchange chromatography techniques. S-sulphocysteine being destroyed during acidic hydrolysis was identified after enzymic hyrolysis of dialyzed and lyophilized filtrates. This result indicates that sulphitolysis occurs during kerationlysis performed by K. ajelloi. As thiosulphuric esters were shown present in hair perforations made by Microsporum gypseum, we think sulphitolysis is a common mechanism developed by dermatophytes to attack keratin.