Question

What is the name of the enzyme required to turn folate into the form used in purine synthesis? How many steps are required to carry out its job? What exactly does the enzyme do? and where in purine/pyrimidine metabolism does inhibition have an effect?

Answer 1

The enzyme required to turn folate into a form used for purine synthesis is dihydrofolate reductase, which performs a single-step reaction. Feedback inhibition is a regulatory mechanism in both purine and pyrimidine metabolism, affecting the synthesis of DNA components.

Step-by-step explanation:

The enzyme required to turn folate into the form used in purine synthesis is dihydrofolate reductase (DHFR). This enzyme catalyzes the reduction of dihydrofolate (DHF) to tetrahydrofolate (THF). THF is then further modified to form 10-formyltetrahydrofolate, which is the form used as a one-carbon donor in the synthesis of purines. The reduction of DHF to THF by DHFR is considered a single-step reaction that is crucial for the formation of THF, necessary for DNA synthesis and repair. When considering the regulation of purine and pyrimidine metabolism, it's important to note that feedback inhibition can occur. For instance, in purine metabolism, the first committed step of the pathway is subject to feedback inhibition which helps to regulate the pathway. An example of feedback regulation in this pathway is the inhibition of glutamine- phosphoribosylpyrophosphate amidotransferase by purine nucleotides (AMP, GMP and IMP). Inhibition in purine and pyrimidine metabolism can lead to a reduction in nucleotide synthesis and can thereby affect DNA replication and repair processes.