Sulfur-containing amino acids of the polyhedral protein of the silkworm yellows virus

Conclusions 1. The polyhedral protein of silkworm virus yellows isolated by the alkali method does not contain sulfhydryl groups.2. The content of sulfhydryl groups in the reduced polyhedral protein has been determined by titration with methylmercury nitrate and by means of Ellman's reagent (0.029–0.033 µmole of SH groups per mg of protein). The content of S-carboxymethylcysteine groups in acid hydrolysates of reduced and carboxymethylated polyhedral protein has been determined with an amino acid analyzer (0.03 µmol/mg).3. The content of cysteic acid in acid hydrolysates of oxidized polyhedral protein is 0.069 µmole/mg.Khimiya Prirodnykh Soedinenii, Vol. 4, No. 3, pp. 174–178, 1968