Question

Which of the following statements concerning biotin functions are true: 

a) Active functional form is pyridoxal phosphate, which is an essential coenzyme for transamination and decarboxylation of amino acids in more than 50 different enzyme systems 

b) Essential constituent of coenzyme A, the important coenzyme for acyl transfer in the TCA cycle and de novo fatty acid synthesis 

c) An extremely important antioxidant, which protects cell membrane lipids from peroxidation by breaking the chain reaction of free radical formation to which polyunsaturated fatty acids are particularly vulnerable 

d) Coenzyme for several reactions involving CO₂ fixation into various compounds e.g. acetyl CoA to malonyl CoA (acetyl CoA carboxylase) – initial step in de novo fatty acid synthesis; propionyl CoA to methylmalonyl CoA (propionyl CoA carboxylase), pyruvate to oxaloacetate (pyruvate carboxylase)  

Answer 1

d) Coenzyme for several reactions involving CO₂ fixation into various compounds e.g. acetyl CoA to malonyl CoA (acetyl CoA carboxylase) – initial step in de novo fatty acid synthesis; propionyl CoA to methylmalonyl CoA (propionyl CoA carboxylase), pyruvate to oxaloacetate (pyruvate carboxylase)