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

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

ANSWER DOWNLOAD EXAMIANS APP

Enzymes
Which of the following is false statement with regard to comparison between Serine and HIV proteases?

Both require water to complete the catalytic cycle
Both forms an acyl-enzyme intermediate
Both show specificity for certain amino acid sequences
Both use nucleophilic attack to hydrolyze the peptide bond

ANSWER DOWNLOAD EXAMIANS APP

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

ANSWER DOWNLOAD EXAMIANS APP

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

ANSWER DOWNLOAD EXAMIANS APP

Enzymes
The E.coli pyruvic acid dehydrogenase complex is reported to

Catalyze the reduction of pyruvic acid to acetyl Co A and CO2
decatalyze the oxidation of pyruvic acid to acetyl Co A and CO2
Catalyze the oxidation of pyruvic acid to acetyl Co A and CO2
retard the reduction of pyruvic acid to acetyl Co A and CO2

ANSWER DOWNLOAD EXAMIANS APP

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

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
Enzymes speed up reactions by lowering activation energy

ANSWER DOWNLOAD EXAMIANS APP