Nucleotide Metabolism | Regulation of Purine Biosynthesis

The video tutorial covers the biosynthesis of purines, focusing on the synthesis of IMP and its conversion into AMP and GMP. It explains the regulation of these pathways, highlighting the role of allosteric enzymes like adenylyl succinate synthetase and IMP dehydrogenase. The tutorial also discusses the feedback inhibition mechanisms that balance purine levels in cells. Additionally, it covers the regulation of PRPP synthetase, emphasizing its role in nucleotide synthesis and how energy charge affects its activity. The video concludes with a summary of the key regulatory points in purine biosynthesis.

What is the initial substrate in the synthesis of IMP?

• Adenosine monophosphate

• Ribose 5 phosphate

• Glutamine

• Guanosine monophosphate

Which enzyme converts ribose 5 phosphate into PRPP?

• Adenylosuccinate synthetase

• IMP dehydrogenase

• PRPP synthetase

• Glutamine PRPP amido transferase

How does AMP regulate its own synthesis?

• By inhibiting adenylyl succinate synthetase

• By activating IMP dehydrogenase

• By increasing PRPP levels

• By converting into GMP

What happens when both AMP and GMP levels rise significantly?

• They increase ribose 5 phosphate levels

• They convert into pyrimidines

• They inhibit glutamine PRPP amido transferase

• They activate PRPP synthetase

Which molecule is NOT an allosteric regulator of glutamine PRPP amido transferase?

• NAD

• IMP

• GMP

• AMP

What is the role of IMP in purine biosynthesis regulation?

• It converts into pyrimidines

• It activates PRPP synthetase

• It inhibits glutamine PRPP amido transferase

• It increases ribose 5 phosphate levels

What is the primary allosteric regulator of PRPP synthetase?

• CTP

• GTP

• ADP

• ATP

In what condition is PRPP synthetase most active?

• During starvation

• High ATP to ADP ratio

• Low energy charge

• High ADP to ATP ratio

Which enzyme is responsible for converting AMP into ADP?

• Nucleoside diphosphate kinase

• Adenylosuccinate synthetase

• PRPP synthetase

• IMP dehydrogenase

Which of the following is a committed step in purine biosynthesis?

• Conversion of IMP to GMP

• Conversion of IMP to AMP

• Conversion of ribose 5 phosphate to PRPP

• Conversion of PRPP to 5-phosphoribosylamine