Ovalbumin disulfide bonds

The liberation of sulfhydryl groups was not detected after irradiation of 0.5% ovalbumin solutions. Since it was shown that the presence of inert protein protected, rather than inactivated, phenolase, it was concluded that thiol groups, produced by disruption of disulfide bonds in the protein, had no significant role in phenolase inactivation. 

Table I summarizes the sequencing results from alcohol dehydrogenase and the N-terminally blocked glycoprotein ovalbumin. The probable identity of these fragments is indicated. All fragments identified for both proteins by N-terminal sequencing corresponded to cleavage after cystine. The data from ovalbumin are particularly interesting. The structure of ovalbumin is well characterized (5) and contains only one disulfide bond between Cys 73 and Cys 120 yet sequence was obtained following Cys 11 and Cys 30. The bands for these fragments appeared more slowly than the odiers and were fainter in appearance.

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