Question

Leucine biosynthesis occurs in a multistep pathway starting from 2-oxovalerate, and the final product of the pathway (leucine) inhibits the first enzyme involved in the biosynthetic pathway through a process called feedback inhibition. This enzyme inhibition occurs, regardless of whether or not the 2-oxovalerate substrate is bound in the active site of the enzyme. Describe what type of inhibitor leucine is and justify your response.

Answer 1

it is a type of mixed inhibition referred to as 'non-competitive inhibition'

Step-by-step explanation:

Mixed inhibition occurs when an inhibitor binds to the enzyme in a site different from the active site where the substrate binds (i.e., the allosteric site). The term 'mixed' is because this inhibition is a mixture of competitive inhibition, where the inhibitor competes with a substrate to bind to the enzyme, and uncompetitive inhibition, where the inhibitor binds only to the complex formed between the enzyme and its substrate. In competitive inhibition, the maximal velocity of the reaction (Vmax) does not change, whereas the apparent Km (i.e., the concentration of substrate which permits the enzyme to achieve half Vmax) increases. ​Moreover, in non-competitive inhibition, the Km does not change, whereas the Vmax decreases. Non-competitive inhibition is a special type of mixed inhibition where the apparent Vmax (V app-max) is reduced, while the Km of the enzyme is unaffected.