FIGURE 4.

Autophosphorylation of MbSrc1. A, MbSrc1 (10 μl of 46 μm) was incubated with immobilized GST-YOP in 30 mm Tris (pH 7.5), 10 mm MgCl₂ (200-μl final volume). The reaction was mixed at room temperature for 30 min. After removal of GST-YOP by centrifugation, MbSrc1 was assayed directly or after incubation with 0.5 mm ATP for 30 min at 30 °C. B, YOP-treated MbSrc1 and untreated MbSrc1 were incubated with 0.5 mm ATP at 30 °C. Aliquots were removed at the indicated times and analyzed by Western blotting with anti-phosphotyrosine antibody.