Regulation of Purine Biosynthesis

The video tutorial explains the regulation of purine synthesis, focusing on key enzymes like PRPP synthetase and glutamine PRPP aminotransferase. It discusses how these enzymes are regulated by energy levels and end products such as AMP, GMP, and IMP. The tutorial also covers feedback inhibition mechanisms in the synthesis pathways of AMP and GMP, highlighting the importance of energy charge and product levels in controlling enzyme activity.

What is the role of PRPP synthetase in purine synthesis?

• It converts ribose 5-phosphate to PRPP.

• It converts PRPP to phosphoryl amine.

• It is not involved in purine synthesis.

• It inhibits purine synthesis.

Which molecule inhibits PRPP synthetase when energy levels are low?

• GMP

• ATP

• AMP

• ADP

How do high levels of IMP affect glutamine PRPP aminotransferase?

• They have no effect on the enzyme.

• They inhibit the enzyme.

• They convert the enzyme to another form.

• They activate the enzyme.

Which enzyme is inhibited by AMP to prevent its own synthesis?

• PRPP synthetase

• IMP dehydrogenase

• Glutamine PRPP aminotransferase

• Adenylosuccinate synthetase

What is the role of GMP in its own synthesis regulation?

• It activates adenylosuccinate synthetase.

• It inhibits IMP dehydrogenase.

• It converts to AMP.

• It has no effect on its own synthesis.

How does high AMP affect glutamine PRPP aminotransferase?

• It converts the enzyme to another form.

• It completely inactivates the enzyme.

• It has no effect on the enzyme.

• It slightly slows down the enzyme.

What happens when both AMP and GMP levels are high?

• Glutamine PRPP aminotransferase is activated.

• Purine synthesis is accelerated.

• Glutamine PRPP aminotransferase is significantly slowed down.

• IMP dehydrogenase is activated.