Keratin degradation, mechanisms

Table 6.1 Comparison of Mechanisms of Keratin Degradation by a Dermatophyte Fungus with That of an Actinomycete...

Kunert, J. (1989a). Biochemical Mechanism of Keratin Degradation by the actino-mycete Streptomyces fradiae and the fungus Microsporum gypseum a comparison. /. Basic Microbiol. 29, 597-604. 

Cooperative mechanism disuifide reductase (disuifide bond reducing) and peptidases (cieaving peptide bonds in keratin). This mechanism was described by Yamamura et ai. (2002) in Stenotrophomonas sp. None of these enzymes showed keratinoiytic activity independentiy and the cooperative action of the two enzymes resuits in the effective degradation of keratin. Extraceiiuiar peptidases acted on the dissociated poiymers, hydroiyzing them into peptides/amino acids... 

At the time, model reactions for (VIII) were known, but no simple analogy for (VII) had been discovered. Schoberl and Wagner (1956), however, showed that the treatment of uncombined cystine with alkali leads to the formation of some lanthionine and, hence, the reaction with the protein was not unique. There has been considerable discussion about the extent to which the lanthionine reaction can account quantitatively for the alkaline degradation of the cystine of keratins and about the mechanism of the reaction. 

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