[Subfractional composition and structural characteristics of G immunoglobulins in pathological states]

Physico-chemical properties of gamma-globulin fraction and immunoglobulins G (IgG) were studied, using temperature-perturbational differential spectrophotometry and ion exchange chromatography on DEAE cellulose, in blood serum of 118 patients with impairments of thyroid gland and of 28 patients with chronic pneumonia. Amount of tyrosine residues, perturbated by temperature, was decreased and an alkaline subfraction was increased in IgG of patients with toxic goiter and chronic pneumonia; the increase in the alkaline subfraction was more distinct in impairments of thyroid gland. The data obtained suggest that the alkaline subfraction is characterized by an increased rigidity and apparently by altered structural properties in toxic goiter. The tyrosine residues in IgG enable to evaluate effectively the availability of a cavity between variable domains (antigen-antibody site) of the immunoglobulin.