Enhancement by sulphate of enzyme activity in the synthesis direction for wild-type and mutated forms of Cc GlgP. A: Effect of sulphate on Vs for the wild-type phosphorylase. (full circles), 25 nM protein, 50 mM G1P; (full triangles) 25 nM protein, 5.0 mM G1P; (open circles), 50 nM protein, 50 mM G1P. Starch (20 g/l) was the acceptor substrate. B: Specific activities (grey bars; left y-axis) for wild-type and mutated phosphorylases determined at a protein concentration of 2.5 nM in the absence of (NH4)2SO4 using 50 mM G1P and 20 g/l maltodextrin as substrates. Relative enhancement of the respective activity by 10 mM (NH4)2SO4 is shown with black bars (right y-axis). All results are representative data.