240 



KERATIN AND KERATINIZATION 



of some structural significance in rendering the formation of regular helices 

 more difficult (p. 193). 



Other oxidizing reagents which destroy cystine bridges (hydrogen 

 peroxide, chlorine, chlorine peroxide, etc.) have been less used and appear 

 less satisfactory. Das and Speakman (1950) demonstrated a variety of 

 polypeptides in extracts of wool oxidized by chlorine peroxide. The 

 molecular size was of a similar order to that found in sulphide extracts. 



Table 16. Analysis of a- and )/-Keratose (Oxidized 

 Wool). (Corfield et al, 1958.) 



(% of total nitrogen) 



The arrows indicate an increase ( t ) or decrease 

 ( 4- ) of a residue in the y-fraction relative to that of the 

 original wool. 

 * Too high according to Gillespie et al. (1960). 



Performic acid, which may have a more specific action, has also attracted 

 some attention (Thompson et al., 1959; Gillespie et al., 1960). 



Thiogly collate extracts. The original method of Goddard and Michaelis 

 (1934), who introduced the use of thioglycollic acid as the reducing agent, 

 also pointed to the existence of two different types of protein in extracts of 

 reduced keratin or kerateine. This method is undoubtedly one of the best 

 solubilization techniques since it i s in a sense reversible, insoluble disul- 

 phide cross-linked powders being obtained by oxidation of kerateines. 



