Question

Some archaebacteria produce an enzyme with two active sites: one catalyzes the de-phosphorylation of fructose-1,6-bisphosphate, and one catalyzes the condensation of dihydroxyacetone phosphate and glyceraldehyde-3-phosphate. Explain the advantage of combining these catalytic activities in a single bifunctional enzyme.

Short answer

In archaebacteria, de-phosphorylation of fructose-1,6-bisphosphate, and condensation of dihydroxyacetone phosphate and glyceraldehyde-3-phosphate take place one after the other. Both of these activities are combined in a single enzyme to save energy and time. This also helps in the maintenance of 2 reactions at a time.

Step-by-step solution

Regulation of Bifunctional Enzyme.

Regulation is explained with an example. These bifunctional enzymes in animals are seen to be regulated by a variety of allosteric effectors and also by phosphorylation and de-phosphorylation as catalyzed by PKA and a phosphoprotein phosphatase. This will create a proper balance between gluconeogenesis and glycolysis under hormonal control.

Archaebacteria

Archaebacteria can be known as single-celled organisms. These microorganisms lack cell nuclei, because of which they are known as prokaryotes.