Presence of phospho-tyrosine in alkaline hydrolysate of pig skeletal muscle myosin.

A small part of the P-containing fraction of myosin hydrolysate which could be eluted with basic solvent (triethylamine) buffer was accumulated on chromatographic column. On the basis of the elution profile, P- and tyrosine content determination, moreover the thin layer chromatographic separation and specific Tyr reaction, this fraction is suggested to be phosphotyrosine. The concentration of P-Tyr is about 2 mol in pig muscle myosin calculated for 500 kDa protein. As the higher P-containing myosins also have an approx. 2 mol P-Tyr, it is thought that this concentration had been present in myosins already before alkaline hydrolysis.