Question

Why is triose phosphate isomerase considered to be catalytically perfect?

Short answer

Triose phosphate isomerase is considered catalytically perfect because of its kcat/Km value which is in the diffusion-limit range.

Step-by-step solution

Role of triose phosphate isomerase

During glycolysis, the reversible interconversion of the triose phosphate isomers dihydroxyacetone phosphate (DHAP) and D-glyceraldehyde 3-phosphate (GAP) is catalyzed by triose-phosphate isomerase.

Triose phosphate isomerase is considered catalytically perfect

Triose phosphate isomerase is a catalytically perfect enzyme because its kcat/Km value is in the diffusion-limited range. The product formation happens as soon as the enzyme and its substrate collide in the solution. As a result, any improvement in the enzyme's catalytic efficiency will not enhance its reaction rate.

The concentrations of GAP and DHAP are kept at their equilibrium values because they are interconverted so efficiently by triose phosphate isomerase.