Figure 1
From: Inhibition of secreted phospholipase A2 by neuron survival and anti-inflammatory peptide CHEC-9
Lineweaver-Burke double reciprocal plots showing CHEC-9 inhibition of sPLA2 group I. The 10-pyrene substrate, at concentrations between 2 and 7 μM, was reacted with 5 nM sPLA2 and CHEC-9 at 0, 0.1, 1.0, and 10 nM. Plots of 1/Vo against 1/[substrate, S] gave convergent lines at higher values of 1/[S] (lower substrate concentrations) suggesting that the inhibition was dependent on substrate concentration. Plots of the apparent inhibition constant KiNR vs. [S] (upper left) showed an overall decline in this value with increasing substrate concentration for each peptide concentration which is characteristic of an uncompetitive inhibitor. This is confirmed by computation of the kinetic parameters shown in Table 1 after fitting the data to the Michaelis-Menton hyperbola. [r2, p values for linearity of reciprocal plots: 0 nM – 0.945, 0.0012; 0.1 nM – 0.947, 0.0011; 1.0 nM – 0.868, 0.0069; 10 nM – 0.810, 0.0145].