True about competitive inhibition of enzyme

It is obvious that in the case of competitive inhibition, the Km is increased in presence of competitive inhibitor. Thus competitive inhibitor apparently increases the Km. In other words, the affinity of the enzyme towards the substrate is apparently decreased in presence of the inhibitor.In competitive inhibition, the inhibitor will be a structural analog of the substrate. There will be similarity in three-dimensional structure between substrate (S) and inhibitor (I). For example, the succinate dehydrogenase reaction is inhibited by malonate (Fig. 5.19). v. Competitive inhibition is usually reversible. Or, excess substrate abolishes the inhibition. In the previous example of 100 moles of E and 100 moles of I, if 900 moles of S are added, only 1/10th of enzyme molecules are attached to the inhibitor and 90% are working with substrate. Thus 50% inhibition in the first example is now decreased to 10% inhibition But Vmax is not changed. Clinical significanceof such inhibitionRef: DM Vasudevan, Page no: 52