Question

Formation of Product by ACE 10 S] (mM) 4 2 0.5 t (min) 50 100 150 200 250 300 Each curve represents sets of three identical reactions. All sets use the same amountof enzyme, but different initial substrate concentrations labelled on the right. None of these reactions involve an inhibitor. A Lineweaver-Burke, or double reciprocal, plot needs 1/[S] and 1/v for the X and Y axes, respectively. Eq. 7-5 states that v changes during the experiment. d[P] dt , or in other words, v is the slope. But the slope Question 2: Where along the time (x) axis should we take the slope to best describe the function of this enzyme?

Answer 1

Here v=d[P]/dt is the rate of formation of product or can be said rate of reaction. If we see the plots at different substrate concentration these are steeply rise initially (around till 50 min) then become almost parallel to the x-axis. it means at some increased time the rate of product formation is decreased. Or the rate is dependent on time or instanteneous concentration of the substrate. So we should take the slope along the time axis with initial periods (the range of 0 min. to 50 min. can be choosed in these particular plots). So we get actual instanteneous rate of the enzymatic reaction during initial period of time. As it is clear from the plots that the slope value will we lowest for 0.5 mM substrate concentration which increases gradually till 10 mM.