Help me! (Michaelis-Menton kinetics)

Jenjey

Jenjey

Jenjey

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Hmm...this is one of the only things I get a wee bit confused on in my whole course so far!! :o
Basically, if anyone is good with this stuff can you just explain Michaelis menton kinetics (all the vmax, km malarky) and explain why vmax/km change in different types of inhibition!

Someone must know!

I'll be soooo grateful for any help, merci :) xoxo
 
In non competetive inhibition, the inhibitor does not resemble the substrate, but still binds and impairs catalytic activity. However the substrate can still bind to the enzyme as usually, except that there will be less conversion to enzyme+product because of the 'damaged' enzyme. Because the substrate can still bind as normal, Km is unchanged, since Km relates to the affinity between enzyme and substrate. (Remember low Km = high affinity, high Km = low affinity). Vmax is decreased because you are basically reducing the concentration of the enzyme.

In competetive inhibition, the inhibitor takes the shape of the substrate, competing for the binding site. This therefore prevents some substrate from binding, causing Km to be increased (i.e. low rate of enzyme-substrate complex being formed). Vmax remains unchanged in this case since there is no effect on activity of the enzyme.
 
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