In which type of inhibition is Km unchanged?

In non-competitive inhibition, the inhibition occurs when an inhibitor binds to an enzyme regardless of whether the substrate is present or not. As a result of this binding, the maximum velocity (Vmax) of the reaction is decreased because the inhibitor interferes with the enzyme's ability to produce product, even if the substrate is fully saturated. However, the affinity of the enzyme for the substrate, represented by the Michaelis constant (Km), remains unchanged. This happens because the non-competitive inhibitor does not compete with the substrate for the active site; instead, it binds to a different site on the enzyme or the enzyme-substrate complex. Thus, the substrate can still bind to the active site, but the overall reaction rate is affected by the presence of the inhibitor.

Competitive inhibition, on the other hand, does change Km. In competitive inhibition, the inhibitor competes with the substrate for binding to the active site, which increases the apparent Km value because a higher concentration of substrate is required to achieve half-maximal velocity.

Uncompetitive inhibition operates differently: it binds only to the enzyme-substrate complex, which reduces both Vmax and Km, thus affecting both parameters.

Allosteric inhibition involves regulators that bind to sites other than the active site,