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Allosterically Regulated

I have attached the five questions and my proposed answers. Please look over them and if they are incorrect, please correct them. I appreciate the help.

1. Since allosteric proteins change shape, in order to perform other biological functions and bind with cofactors, I would say the primary level of protein structure, answer A.

2.I think the answer is B because of catlysis of of phosphorylation of substrates by transferring a phosphate from ATP. There is no mention of sulfur groups.

3. I would chose a B, because the regulatory site of an enzyme is the binding site for non-competitive inhibitors.

4.Not quite sure

5. According to Michaelis-Menton, Km is the substrate concentration which yields half-maximal velocity, where as Vmax is the maximum velocity. Non-competitive inhibition yields a change in the shape of an enzyme.This reduces the concentration of 'active' enzyme resulting in a decrease in the Vmax. Thus I would chose answer E

Question #1: (0.8 point)
Which level of structure must a protein have to be allosterically regulated?
a.) Primary
b.) Secondary
c.) Tertiary
d.) Quaternary
e.) All of the above

Question #2: (0.8 point)
Which of the following is not a mechanism of enzyme regulation?
a.) Feedback inhibition by product.
b.) Addition or removal of phosphate groups to amino acids with sulfur groups.
c.) Stimulation by a substrate or product.
d.) Proteolytic cleavage
e.) None of the above

Question #3: (0.8 point)
Which of these is NOT a function or capability of the active site of an enzyme?
a.) Substrate binding
b.) Binding of a necessary cofactor
b.) Binding a non-competitive inhibitor
c.) None of the above
d.) All of the above

Question #4: (0.8 point)
The Km of an enzyme:
a.) is equal to the maximal velocity of an enzyme
b.) is a hypothetical number that cannot be determined experimentally
c.) is negatively affected by a non-competitive inhibitor
d.) is a measure of how tightly an enzyme binds to its substrate
e.) all of the above

Question #5: (0.8 point)
a.) is the maximal velocity at which an enzyme can function
b.) is reduced by a non-competitive inhibitor
c.) is determined on a Lineweaver-Burke plot by taking the reciprocal of the y-intercept
d.) is high for an enzyme with a high Km and low substrate affinity
e.) all of the above

Solution Preview

1. Allosteric regulation is regulation caused by the interaction of subunits. Therefore, a protein must have quaternary structure in order to have allosteric regulation. In other words, only multisubunit proteins can be allosterically regulated.

2. Phosphate groups are not added to sulfur atoms. They are added to oxygens, in hydroxyl groups, for ...

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