Avidin is a protein from egg white. It has very high affinity to biotin and because of that works as a highly specific inhibitor of biotin enzymes. Which of the following conversions would be blocked by the addition of avidin to a cell homogenate?

(a) Glucose → pyruvate

(b) Pyruvate → glucose

(c) Oxaloacetate → glucose

(d) Malate → oxaloacetate

(e) Pyruvate → oxaloacetate

(f) Glyceraldehyde 3-phosphate → fructose 1,6-bisphosphate

Explanation:

1. Avidin is a glycoprotein,  four identical subunits are there in avidin. It is found in white part  of the egg of reptiles, amphibians, and birds.

2. Avidin binds in specific manner with biotin.

3.  Avidin  is resistant to some of the enzymes like  pancreatic enzymes.

4. The conversions of Pyruvate into glucose and  and the conversion of  Pyruvate  into oxaloacetate would be blocked if  the  avidin is added  to a cell homogenate.