Enzyme regulation

The allosteric inhibitor of an enzyme

• Causes the enzyme to work faster

• Binds to the active site

• Participates in feedback regulation

• Denatures the enzyme

Removal of phosphoryl groups is catalyzed by

• ATCase

• Dinitrogenase reductase

• Protein phosphatases

• Protein kinases

Which of the following is false about the following reaction?

Phosphorylase a + 2H2O → phosphorylase b + 2Pi

• Phosphorylase a is less active and phosphorylase b is more active

• Glycogen phosphorylase catalyzes this reaction

• Phosphorylase b can be transformed back into phosphorylase a by phosphorylase kinase

• Phosphorylase kinase catalyzes the transfer of phosphoryl groups from ATP to Phosphorylase b

Which of the following is false?

• Allosteric modulators may be inhibitory or stimulatory

• Based on the nature of modulator, allosteric enzymes are of two types

• Homotropic allosteric enzymes have the substrate and modulator same

• Heterotropic allosteric enzymes have the substrate and modulator same

In the case of allosteric enzymes what is the graphical representation when initial velocity is plotted against substrate concentration?

• Hyperbola

• Sigmoid curve

• Straight line with negative slope

• Parabola

Which is the enzyme that acts as a regulatory enzyme in a four-step metabolic pathway?

• First enzyme

• Fourth enzyme

• Second enzyme

• Third enzyme

What is an example of an allosteric activator?

• ddATP

• AMP

• ATP

• cAMP

How many subunits are there in ATCase

• 12 regulatory and 12 catalytic

• 6 regulatory and 6 catalytic

• 12 regulatory and 6 catalytic

• 6 regulatory and 12 catalytic

CTP is

• Substrate

• Allosteric inhibitor

• Allosteric activator

• transition state analogue

PALA is

• Bisubstrate analogue

• Allosteric inhibitor

• Allosteric Activator

• Zymogen