Most examples of competitive inhibition are reversible, meaning that the enzyme is not permanently altered and the inhibition process is reversible.
In competitive inhibition, the Vmax stays the same, because the inhibitor does not alter the enzyme's ability to act on the substrate. The competitive inhibitor only competes with the substrate for binding to the active site.
In this type of inhibition, the inhibitor and substrate are competing to bind to the active site of the enzyme. This means that the inhibitor-enzyme complex is weak, because a substrate can outcompete it.
The substrate concentration at half of Vmax is Km. Km increases with competitive inhibition, because more substrate is needed to out-compete the inhibitors for binding to the active site. Thus, in order to reach Vmax (or half Vmax), the substrate concentration must be higher, thus a larger Km.
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