Table 2

Kinetic parameters of glyoxalase I, GST P1-1/Ile-105, and GST P1-1/Val-105

Enzyme	K_I^{TER 117}	K_I^GSH^2-a	K_m^MG-SG^2-a	K_m^CDNB^2-b	K_m^GSH^2-b
	μM	μM	μM	mM	mM
GST P1-1/Ile-105	0.14 ± 0.03^2-c			0.36 ± 0.02	0.25 ± 0.01
GST P1-1/Val-105	0.12 ± 0.02^2-c			0.70 ± 0.04	0.14 ± 0.01
Glyoxalase I	0.56 ± 0.05^2-d	145 ± 38	21 ± 5

Measurements were carried out in 1 ml of 0.1 M sodium phosphate, pH 7.0, at 30°C. In measurements involving GST P1-1, the concentrations of CDNB and GSH ranged between 0.15 and 1.8 mM and between 0.2 and 2.0 mM, respectively. In measurements with glyoxalase I, the concentrations of MG-SG and GSH ranged between 20 and 400 μM and between 0.2 and 2.0 mM, respectively.

↵2-a K _I ^GSH andK _m ^MG-SG were determined by fitting eq. 1 to the inhibition data using nonlinear regression.
↵2-b K _m ^CDNB andK _m ^GSH were determined by nonlinear regression analysis by fitting eq. 3 to the experimental data.
↵2-c K _I values for GST P1-1 were determined by varying TER 117 at seven concentrations between 0 and 8 μM. The concentration of CDNB was kept constant at 1 mM and the concentration of GSH ranged between 0.2 and 2.0 mM. K _I values for GST P1-1, extrapolated to zero GSH concentration, were determined by nonlinear regression analysis by fitting eq. 3 to the experimental data.
↵2-d The K _I value for glyoxalase I was determined by varying TER 117 at five concentrations between 0 and 5 μM. The concentration of free GSH was kept constant at 0.2 mM and the concentration of MG-SG ranged between 20 and 400 μM. TheK _I ^{TER 117} value for glyoxalase I extrapolated to zero GSH concentration was determined by nonlinear regression analysis using eq. 2.