Biopolymers and cell. 1996; 12 (5): 21 - 28

Autoantibodies directed against tyrosyl-tRNA synthetase modulate its aminoacylating activity

L. L. Sidorik, N. V. Rodnin, Z. A. Savinskaya, T. A. Ribkinska.O. T. Rozhko, A. I. Korneliuk, G.H.Matsuka

The autoantibodies directed against many proteins and ribonucleoproteids, the components of translation apparatus, have been detected at several systemic autoimmune diseases. Earlier we revealed the autoan¬tibodies against setyl-tRNA synthetase in the blood sera of patients with systemic lupus erythematosus and rheumatoid arthritis. In the present paper we report about the autoantibodies directed against tyrosyl-tRNA synthetase, the other translation apparatus component. While the polyclonal antibodies inhibited the aminoacylating activity ofTyrR S down to 30 % the autoantibodies from autoimmune sera activated it up to 280 % that hasn't been observed for any other synthetase. The possible reasons of this phenomenon are discussed.