The reaction of oxidizing agents with wool. 4. The reactivity of tyrosine

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Abstract
A study was made of the reaction of different oxidizing agents with the tyrosine in wool, horn, silk, solubilized keratin, tyrosylglycine, glycyltyrosine, glycyltyrosylglycine. Chlorine and hypochlorous acid oxidize all the tyrosine in wool, whereas acid permanganate and alkaline hypochlorite oxidize only 30% of the tyrosine present. The tyrosine in wool may therefore be divided into 2 fractions, one oxidized by the latter 2 reagents and the other not. Peracetic acid does not oxidize the tyrosine in any of the materials studied. There is no evidence for tyrosine fractions of different reactivity in silk or the high molecular weight keratin alpha-keratose rendered soluble by oxidation. More than twice as much chlorine is required at pH 10 than at pH 2 to oxidize the same amt. of tyrosine in silk and alpha-keratose, whereas chlorine and hypochlorite are equally effective in oxidizing the tyrosine in simple peptides and low molecular wt. fractions of wool. The difference in reactivity of the 2 tyrosine fractions in wool is explained in terms of the structure for wool proposed by Alexander (1950).
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