Secondary plots to determine K
for the alkaloids for GST Sigma with CDNB as the substrate. A Non-competitive inhibition was obtained with respect to CDNB, and a re-plot of 1/Vmax versus [I] was used to determine Ki
CDNB. In B, a replot of Km/Vmax versus [I] was used to determine Ki′CDNB for the alkaloids. The X- intercept as indicated by the arrow gave the value -Ki which was used to calculate the Ki and K΄i respectively. These gave values of Ki and Ki′ of 7.7 and 9.2 μg/ml. Correlation coefficients of 0.84 and 0.99 were obtained for plots A and B respectively.