Four of the ten enzymes required for the biosynthesis of IMP are listed below.In which order do the reactions these enzymes catalyze occur during the synthesis of IMP?
1.IMP cyclohydrolase
2.GAR synthase
3.glutamine-PRPP amidotransferase
4.AIR carboxylase

Question

Four of the ten enzymes required for the biosynthesis of IMP are listed below.In which order do the reactions these enzymes catalyze occur during the synthesis of IMP? 
1.IMP cyclohydrolase
2.GAR synthase
3.glutamine-PRPP amidotransferase
4.AIR carboxylase

Quizplus · Accepted Answer

The order of reactions in the biosynthesis of IMP is as follows:
1. Glutamine-PRPP amidotransferase catalyzes the conversion of PRPP and glutamine to 5-phosphoribosylamine.
2. GAR synthase catalyzes the conversion of 5-phosphoribosylamine to GAR.
3. AIR carboxylase catalyzes the conversion of GAR to CAIR.
4. IMP cyclohydrolase catalyzes the conversion of CAIR to IMP. Therefore, the correct order is 3 → 2 → 4 → 1, which is option C.

Four of the Ten Enzymes Required for the Biosynthesis of IMP