Figure 4.
Comparison of inhibition of WT by L-glutamate (closed circles) and activity in the W138F/M141R mutant (open circles). The lines represent fits to eq. 2 for WT and the Michaelis-Menten equation for W138F/M141R. Experimental conditions for WT: 100 mM TEA succinate pH 7.8, 100 mM dipotassium succinate, 20 mM AIB, 2 mM pyruvate, 20 µM PLP, 1 unit/mL 2° ADH, 300 µM NADPH and varying concentrations of L-glutamate. Experimental conditions for W138F/M141R: 30 mM TEA-succinate pH 7.8, 50 mM dipotassium succinate, 5 mM DTT, 1 mM EDTA, 20 µM PLP, 500 µM NADP+, 5 mM α-ketoglutarate, 3 units/mL SSDH and varying concentrations of L-glutamate.