Enzymes Flashcards

Flashcards about Enzymes

What are Enzymes?

Mostly proteins and biological catalysts that increase the rates of chemical reactions without being consumed.

What is Apoenzyme?

The protein part of a conjugated enzyme that is inactive on its own.

What is a Cofactor?

The non-protein part of a conjugated enzyme, essential for the enzyme's activity.

What is a Conjugated Protein (Holoenzyme)?

An enzyme that consists of a protein part (apoenzyme) and a non-protein component (cofactor).

What is a Prosthetic Group?

A cofactor firmly attached to the enzyme, often a metal ion.

What is a Coenzyme?

A cofactor loosely attached to the enzyme, often an organic molecule like a vitamin.

What is the role of Coenzymes?

Small organic molecules that assist enzymes by acting as carriers for chemical groups or electrons.

Examples of Coenzymes

NAD+, NADP+, FAD, Coenzyme A (CoA)

What are Monomeric enzymes?

Enzymes containing only a single polypeptide chain.

What are Oligomeric enzymes?

Enzymes containing two or more polypeptide chains attached by noncovalent bonds.

What is a Proenzyme or Zymogen?

Inactive form of an enzyme.

What is the Active Site?

The region of an enzyme that binds the substrate and participates in making and breaking chemical bonds.

What is the Lock and Key Hypothesis?

The shape relationship between the substrate and the active site is like a key and lock.

What is the Induced Fit Hypothesis?

The substrate binds to the enzyme, inducing a conformational change in the active site.

What are the six main classes of enzymes?

Oxidoreductases, Transferases, Hydrolases, Lyases, Isomerases, Ligases

What reactions do Oxidoreductases catalyze?

Catalyze oxidation and reduction reactions.

What reactions do Transferases catalyze?

Catalyze the transfer of functional groups from one molecule to another.

What reactions do Hydrolases catalyze?

Catalyze hydrolysis reactions (addition of water).

What reactions do Lyases catalyze?

Catalyze the addition to double bonds or the removal of groups by breaking bonds.

What reactions do Isomerases catalyze?

Catalyze isomerization reactions.

What reactions do Ligases or synthetases catalyze?

Catalyze the joining of two molecules by forming bonds with ATP cleavage.

What is Activation Energy?

The amount of energy required to start a reaction.

How do enzymes affect activation energy?

Enzymes lower the activation energy of biochemical reactions.

What factors Influence Rate of Enzyme Action?

Rate of enzyme action, Stereochemistry, pH, Temperature, Concentration of Substrate.

What is an enzyme Inhibitor?

Substance that reduces the velocity of an enzyme-catalyzed reaction.

What is a Reversible inhibitor?

Inhibitor binds to Enzyme reversibly through non-covalent interactions.

What is a Competitive inhibitors?

A competitive inhibitor and enzyme’s substrate are in direct competition for the same binding active site on the enzyme.

What is a Noncompetitive inhibitor?

It occurs when the inhibitors geometry does not resemble the geometry of the substrate, hence no competition occurs.