Protein and Enzymes Sequencing Quiz

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What is the area on the enzyme where the substrate attaches called?

Binding site

Inhibitory site

Catalytic site (correct)

Inactive site

What do we call the substance at the beginning of an enzymatic reaction on which an enzyme acts?

Coenzyme

Substrate (correct)

Activator

Inhibitor

What is the term used for an enzyme without its non-protein moiety?

Coenzyme

Apoenzyme (correct)

Holoenzyme

Prosthetic group

Which type of cofactor is tightly bound to the apoenzyme by covalent bonds?

Prosthetic group Signup and view all the answers

What is the term for a non-protein chemical compound bound to an enzyme and required for catalysis?

Cofactor Signup and view all the answers

What type of cofactor is derived from vitamins and loosely bound to the apoenzyme by non-covalent bonds?

Coenzyme Signup and view all the answers

What is the purpose of using 1-fluoro-2-4-dinitrobenzene (DNB) in sequencing polypeptides?

To label the first amino acid Signup and view all the answers

In Edman Degradation, what does phenylisothiocyanate label?

The first amino acid Signup and view all the answers

What happens if Edman Degradation is repeated several times on a polypeptide?

It allows for the determination of the entire sequence Signup and view all the answers

Under acidic conditions, what happens to the bonds in a polypeptide chain when reacting with Sanger Reagent?

Bonds between certain amino acids break Signup and view all the answers

What is the consequence of using 1-fluoro-2-4-dinitrobenzene (DNB) on the rest of the polypeptide chain?

It destroys the rest of the polypeptide chain Signup and view all the answers

What allows for repeated use of phenylisothiocyanate in Edman Degradation?

Basic conditions Signup and view all the answers

Which environmental factor has the most significant impact on enzyme activity?

Temperature Signup and view all the answers

What is the primary mechanism by which a competitive inhibitor slows down an enzymatic reaction?

It binds to the enzyme's active site, preventing the substrate from binding Signup and view all the answers

What is the optimal pH range for most enzymes?

pH 6 - 8 Signup and view all the answers

How does substrate concentration affect the rate of an enzymatic reaction?

The rate increases until the enzyme is saturated, then remains constant Signup and view all the answers

What is the role of cofactors in enzymatic reactions?

Cofactors are inorganic substances that are necessary for proper enzyme activity Signup and view all the answers

How do competitive inhibitors affect the $K_m$ (Michaelis constant) of an enzymatic reaction?

The $K_m$ increases, indicating lower substrate affinity Signup and view all the answers

What is the main difference between the lock-and-key model and the induced-fit model of enzyme action?

The lock-and-key model involves a rigid active site, while the induced-fit model has a flexible active site. Signup and view all the answers

How does an enzyme increase reaction rates according to the text?

By decreasing the activation energy of the reaction Signup and view all the answers

What happens within the active site of an enzyme-substrate complex?

The reaction occurs to convert substrate to product Signup and view all the answers

What is one limitation of the lock-and-key model of enzyme action?

It cannot explain the flexibility of enzyme active sites Signup and view all the answers

How do enzymes achieve varying degrees of specificity for substrates?

By adjusting their active site and shape to maximize fit Signup and view all the answers

What is the overall reaction for the conversion of substrate to product in enzyme-catalyzed reactions?

$E + S \xrightarrow{ES} E + P$ Signup and view all the answers

Which of the following statements about non-competitive inhibitors is correct?

They bind to a site other than the active site, causing a conformational change that disrupts substrate binding. Signup and view all the answers

Which of the following is a common naming convention for enzymes?

Enzyme names describe the substrate and the function, e.g., alcohol dehydrogenase. Signup and view all the answers

Which of the following is NOT one of the six functional classes of enzymes according to the International Union of Biochemists (I.U.B.)?

Polymerases Signup and view all the answers

What is the biochemical activity of oxidoreductases?

Catalyze the addition or removal of hydrogen atoms in oxidation/reduction reactions. Signup and view all the answers

Which of the following statements about competitive inhibitors is correct?

They bind to the active site of the enzyme, mimicking the substrate. Signup and view all the answers

Which of the following is an example of a common name used for a digestive enzyme?

Trypsin Signup and view all the answers