Biochem!!!Please help some questions have more than one answer. please select th

Question

Biochem!!!Please help some questions have more than one answer. please select the best answer.

1a.Choose all of the following that distinguish positive and negative allosteric effectors. To be distinguishing characteristics the statement must be factually true as written and must pertain to one but not the other types of allosteric effector.

1.) A negative allosteric effector binds the catalytic site.

2. Catalytic rate of the enzyme is increased by reducing the concentration of a negative allosteric effector

3. the Km of the enzyme is increased by increasing the concentration of positive allosteric effector.

4.) a positive allosteric effector binds an allosteric site of the enzyme

Quest1B The velocity of an ezyme catalyzed reaction can be stimulated by an increase in which of the following

1.) concentration negative allosteric effector

2)concentration of positive allosteric effector

3)Increase the total enzyme concentration

4).Km

5. Cofactor concentration

6)substrate concentration

7. competitive inhibitor concentration

Question 1c Choose all of the following that are characteristics of regulation of enzyme catalyzed reactions

1. phosphorylation is a weak interaction of phosphate with a phosphate binding site of the enzyme

2.) velocity may be the same for a reaction in both directions

3. the km of an enzyme is increased by the binding of a negative allosteric effector

4. reactions with a cofactor cannot be regulated by allosteric effector

5. The negative allosteric effector increased the Km of the enzyme for allosteric effector

6. allosteric regulation requires that substrate concentration is varied

Explanation / Answer

1. b) and d)

Allosteric effectors are the compound that bound to the enzyme, at a site other than the catalytic site, but at a site called the allosteric site.

As they dont bind to the catalytic site,they comes under non-competitive inhibition, which doeant affect the km values.

A negative allosteric effectors inhibits an enzyme , so decreasing the concentration of negative allosteric effectors willincrease the enzyme activity.

2.b) and c)

As said earlier, the positive allosteric effector increases the enzyme activity, so increasing the ppoitive effector will increase the velocity of the reaction.

Also , increasing the concentrations of the enzyme also increases the velocity of reactions, this can be demonstrated by plotting a graph between the Vmax vales and the enzyme concentration.

km values, if they are high , they need a high concentration of the substrate to attain the vmax.

3.2)and 3)

As we know, allosteric doesnt bind to the catalytic site, so it doesnt affect the km.

Co factor is a non protein , which causes activation of an enzyme, presence of a co factor doesnt affect the allosteric binding.

So the activation of an enzyme by an co factor is not regulated by the allosteric affector, as allosteric effector binds to an active enzyme.

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