Enzymes
The proteolysis rate enhancement by chymotrypsin (~1010 folds) corresponds to a reduction in activation energy of about

40 kJ/mol
58 kJ/mol
49 kJ/mol
88 kJ/mol

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

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

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

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

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

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

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

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
absence of water in the active site
proximity of Ser 195 to the active site or specificity pocket

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