Enzyme Inhibition

40 Questions

What type of inhibitor binds to an allosteric site on the protein?

Non-competitive inhibitor

What is the effect of a non-competitive inhibitor on the Km and Vmax of an enzyme?

Km remains the same, Vmax decreases

What type of inhibitor binds only to the enzyme-substrate complex?

Un-competitive inhibitor

What is the effect of a competitive inhibitor on the Km and Vmax of an enzyme?

Km increases, Vmax remains the same

What is irreversible inhibition?

Covalent binding of an inhibitor to the active site or an allosteric site

What is the effect of an un-competitive inhibitor on the Km and Vmax of an enzyme?

Km increases, Vmax decreases

What type of inhibitor increases Km, but does not affect Vmax?

Competitive inhibitor

What is the effect of a non-competitive inhibitor on the Lineweaver-Burk plot?

Decreases the slope, increases the y-intercept

What is the name of the method used to linearize the non-linear Michaelis-Menten equation?

Lineweaver-Burk method

What is the effect of a competitive inhibitor on the Km of an enzyme?

It increases the Km

What is the name of the model proposed to describe enzyme kinetics in 1913?

Michaelis-Menten model

What is the term for the regulation of enzyme activity by gene expression?

Gene expression regulation

What is the name of the authors of the biochemistry textbook 'Biochemistry'?

L.Stryer

What is the term for the phenomenon where multiple substrate binding sites are present on an enzyme?

Cooperativity

What is the term for the type of inhibition where the inhibitor binds to an allosteric site on the enzyme?

Allosteric inhibition

What is the term for the type of inhibition where the inhibitor binds to the active site of the enzyme?

Competitive inhibition

Which subunit combination represents the LDH isozyme specific to the skeletal muscle and liver?

MMMM

Which disease is associated with increased levels of all five isozymes of LDH?

Leukemia

What does ELISA stand for?

Enzyme-linked immunosorbent assay

Which enzyme is used as a biomarker for acute pancreatitis?

Amylase

What is the primary location of the HHHH LDH isozyme?

Heart and RBCs

Which enzyme is a diagnostic marker for viral hepatitis?

SGPT

What is the biomedical importance of γ-glutamyl transferase?

Liver disease especially biliary obstruction

What is the principle behind ELISA?

Linking an enzyme to an antibody to detect antigen

Which factor is NOT listed as affecting enzyme activity?

Enzyme color

Why is enzyme expression not useful for rapid adaptation?

It involves the synthesis of new RNA transcripts and proteins

Which condition causes most enzymes to denature?

Temperature above ~50 °C

Which statement best describes feedback inhibition?

A product of a reaction inhibits the enzyme's activity

What happens when effectors bind to the enzyme at the substrate (active) site?

They act as competitive inhibitors

What happens to the reaction rate with a 10 °C temperature rise?

It doubles

How does a change in pH potentially affect enzyme activity?

By altering the enzyme's conformation or the substrate's protonation state

Which type of inhibition is described when the enzyme's activity is regulated by the molecule that binds elsewhere than the active site?

Allosteric regulation

Where do allosteric effectors bind to an enzyme?

At a site different from the substrate binding pocket

What happens to KM during K-type regulation?

KM decreases

What is the effect on Vmax during V-type regulation?

Vmax increases

What is a characteristic of isoenzymes?

They have genetically determined differences in amino acid sequence

Which isoenzyme is associated with cardiac muscle?

CK2

What can happen during mixed forms of allosteric regulation?

Both KM and Vmax can be affected

During enzyme inhibition, which type of inhibitor does not affect the binding of the substrate?