if an Inhibitor is introduced and the Vmax:Km ratio is as follows;
Reaction A: 0.054
Reaction B: 0.877
Reaction C: 1.982
Now if reactions B and C are affected by inhibitors, what is the implication of the ratio
Vmax/Km, or more usually kcat/Km, is a measurement of "catalytic efficiency." For a single-substrate enzyme in Michaelis-Menten kinetics, a competitive inhibitor increases the apparent Km (i.e. it takes a higher substrate concentration to achieve the same rate as without the inhibitor), and a non-competitive inhibitor decreases the apparent Vmax (or kcat). In either case, the ratio Vmax/Km decreases.
In any case, rather than focusing on the effect of an inhibitor on Vmax/Km, it is more useful to figure out what mechanism of inhibition is at work, and to measure the potency of that inhibition (Ki).
Hi there,
Vm/Km ratio is expected to decrease when enzyme is efficiently inhibited with competitive or non competitive inhibitors and is expected to remain the same when submitted to uncompetitive inhibitor. Therefore as there is an increase in the ratio for B and C compared to A (ratio without any inhibitor?), there is a problem... Have you run the all sets of experiments with the same amount of enzyme?
Vmax/Km, or more usually kcat/Km, is a measurement of "catalytic efficiency." For a single-substrate enzyme in Michaelis-Menten kinetics, a competitive inhibitor increases the apparent Km (i.e. it takes a higher substrate concentration to achieve the same rate as without the inhibitor), and a non-competitive inhibitor decreases the apparent Vmax (or kcat). In either case, the ratio Vmax/Km decreases.
In any case, rather than focusing on the effect of an inhibitor on Vmax/Km, it is more useful to figure out what mechanism of inhibition is at work, and to measure the potency of that inhibition (Ki).
To properly answer this questions It is necessary to know if you have used or not the same amount of enzyme in each assay. is reaction A the one without inhibitor? Is your enzyme an allosteric enzyme?
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