Sialic acid in thyroglobulin. II. Influence of sialic acid on ionization of tyrosine residues.
During electrophoresis in polyacrylamide gel at pH 9-5, it was noticed that sialic acid-poor thyroglobulin contains fewer low molecular weight fragments than sialic acid-rich thyroglobulin. Splitting off of sialic acid diminishes thenumber of phenolic groups of tyrosine, MIT, DIT and T4, which dissociate below pH 12-5. This phenomenon was interpreted as a result of lowered hydrophilia of these regions of the thyroglobulin molecule which contains tyrosine and its iodinated derivatives.
Sialic acid in thyroglobulin. II. Influence of sialic acid on ionization of tyrosine residues. During electrophoresis in polyacrylamide gel at pH 9-5, it was noticed that sialic acid-poor thyroglobulin contains fewer low molecular weight fragments than sialic acid-rich thyroglobulin. Splitting off of sialic acid diminishes thenumber of phenolic groups of tyrosine, MIT, DIT and T4, which dissociate below pH 12-5. This phenomenon was interpreted as a result of lowered hydrophilia of these regions of the thyroglobulin molecule which contains tyrosine and its iodinated derivatives.