In which type of enzyme inhibition is Vmax unaffected? Noncompetitive, Competitive, Uncompetitive, or All types of inhibition

##V_"max"## is unaffected by competitive inhibition.

A Lineweaver-Burk plot can distinguish among competitive, non-competitive, and uncompetitive enzyme inhibition.

##1/V = (K_"m" + [S])/(V_"max"[S]) = K_"m"/V_"max" 1/([S]) + 1/V_"max"##

Competitive Inhibition

A competitive inhibitor has a similar shape to the substrate. It binds reversibly at the active site, where it competes with substrate for binding.

##V_"max"## does not change, so ##1/V_"max"## is also unchanged.

But ##K_"m"## changes, so there are different slopes and ##x##-intercepts for the two processes.

Non-competitive inhibition

The shape of a non-competitive inhibitor is different from that of the substrate.

It binds to another site on the enzyme or enzyme-substrate and prevents the formation of products.

It causes a decrease in ##V_"max"## but doesn't change ##K_"m"##, so the plot has the same ##x##-intercept as the uninhibited reaction, but a different slope.

Uncompetitive inhibition

The shape of an uncompetitive inhibitor is different from that of the substrate.

It cannot bind to the active site. It can bind to the enzyme-substrate complex only after it has been formed.

This reduces both ##V_"max"## and ##K_"m"## by the same amount, so the slope does not change but the ##x##-intercept does.

The lines end up parallel to each other.