Enzymes
Tryprotophan synthetase of E.coli, a typical bifunctional oligomeric enzyme consist of

two proteins designated A and B
a protein A and one-subunit a
a protein designated A
a protein designated B

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Enzymes
Before they can react, many molecules need to be destabilized. This state is typically achieved through

oxidizing the molecules by removing electrons
changing the reaction from a biosynthetic to a catabolic pathway
the input of a small amount of activation energy
changing the three-dimensional shape of the molecule

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Enzymes
In the enzyme-catalyzed reaction shown below, what will be the effect on substances A, B, C, and D of inactivating the enzyme labeled E2? A ---(E1)---> B ---(E2)---> C ---(E3)--->

A, B, C, and D will all still be produced
A will still be produced, but not B, C, or D
A, B, and C will still be produced, but not D
A and B will still be produced, but not C or D

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Enzymes
The cleavage specificity of trypsin and chymotrypsin depend in part on the

absence of water in the active site
proximity of Ser 195 to the active site or specificity pocket
presence of a low-barrier hydrogen bond in the active site or specificity pocket
size, shape, and charge of the active site or specificity pocket

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Enzymes
Which of the following statements about enzymes or their function is true?

Enzymes speed up reactions by lowering activation energy
All of these
Enzymes are proteins whose three-dimensional form is key to their function
Enzymes do not alter the overall change in free energy for a reaction

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Enzymes
How is the enzyme COX-1 important in human health?

It catalyzes the production of hormones that maintain the stomach lining
It is critical for the biosynthesis of DNA
It helps to transport carbon dioxide in the blood
It is a chemical derivative of aspirin

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