Sulfhydryl-dependent thermal aggregation of human gamma globulin: augmentation by hyaluronic acid.

Hyaluronic acid (4 mg/ml) augmented elevenfold the copper-catalyzed (7 muM) thermal (63 degrees C, 2 hours) aggregation of human gamma globulin (2 mg/ml) in 0.075 M phosphate buffer, pH 7.4. Almost no augmentation of aggregation occurred with hyaluronidase-treated hyaluronate. Hyaluronate-augmented copper-catalyzed thermal aggregation was inhibited by L-histidine, gold thiomalate, N-ethylmaleimide, p-chloromercuribenzoic acid, and ethylenediaminetetraacetic acid. Together with previous reports of a decreased blood histidine concentration in rheumatoid arthritis, these studies provide a possible explanation for the affinity of this disease for joints.