[T-proteins of Streptococcus pyogenes. IV. Isolation of T1-protein using affinity chromatography on immobilized...

T-protein of Streptococcus pyogenes, type 1 (strain SF 130 Griffith) was extracted by enzymatic treatment of the cells with trypsin and partially purified by ion exchange chromatography on DEAE cellulose and gel chromatography on ultrogel ACA 44. The crude T protein still showing serologically type specific and cross reactions finally was applied to a fibrinogen sepharose column. Components eluted with the neutral buffer (0.05 M phosphate, 0.2 M NaCl, 0.02% NaN3, pH 7.0) reacted serologically in the same manner as the crude T protein. By using 0.1 M citrate, 6 M urea pH 3.0 buffer a type specifically reacting protein (T1-TRYP-F) was eluted from the fibrinogen column. T1-TRYP-F showed identical precipitation lines with the recently characterized T1-protein (T1-TRYP-I) purified by immunochromatography on type specific anti-T antibodies. Comparison of the SDS-patterns of T1-TRYP-F and T1-TRYP-I revealed a less complex molecular size subunit structure for the fibrinogen binding T1-TRYP-F (two bands of 60000 and 70000) as found for T1-TRYP-I, which showed serologically active peptides between 30000 to about 500000. It is discussed that T protein also may be linked covalently with fibrinogen receptors as it has been reported for M protein.