BMF 1: L. 6 Enzymes Overview

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Questions and Answers

What are enzymes?

They decrease reaction rates.

They are a class of proteins. (correct)

They are consumed during biochemical reactions.

They are catalysts that increase reaction rates. (correct)

Describe the general properties of the structure of an enzyme.

Enzymes are linear chains of amino acids that fold to form a three-dimensional structure with an active site.

What are the factors that will influence enzyme activity?

Concentrations of substrates, temperature, pH, presence of activators, inhibitors, and inactivators.

How does increasing the concentration of substrate affect the enzyme reaction rate?

It increases the reaction rate until saturation is reached. Signup and view all the answers

How does increasing the concentration of enzyme affect the reaction rate?

It increases the reaction rate until a saturation point is reached. Signup and view all the answers

How does temperature influence enzyme activity?

It increases activity until the enzyme becomes denatured, after which activity declines. Signup and view all the answers

How does pH influence enzyme activity?

pH affects enzyme activity, with an optimal pH for maximum function and denaturation points. Signup and view all the answers

What are activators, inhibitors, and inactivators?

Activators increase enzyme activity, while inhibitors decrease it. Signup and view all the answers

How are enzymes classified?

Based on the type of reactions they catalyze. Signup and view all the answers

Match the following enzyme classes with their descriptions:

Oxido-reductases = Oxidation-Reduction reactions Transferases = Group Transfers Hydrolases = Cleavage of Bonds with addition of H2O Lyases = Breaking of Bonds without addition of H2O Isomerases = Racemization of isomers Ligases = Bond Formation with energy supplied by high energy compounds like ATP Signup and view all the answers

What are coenzymes?

Nonprotein compounds necessary for enzyme function. Signup and view all the answers

What are prosthetic groups?

Nonprotein groups that are irreversibly bound to enzymes. Signup and view all the answers

What are examples of coenzymes with Oxido-reductases?

NAD+/NADH, NADP+/NADPH, FAD/FADH2. Signup and view all the answers

What are examples of coenzymes with Ligases?

ATP and Biotin. Signup and view all the answers

What are examples of coenzymes with Transferases?

ATP/ADP and Pyridoxal phosphate. Signup and view all the answers

Where are enzymes distributed?

Distributed within cells and tissues as per required reactions. Signup and view all the answers

How do we get different forms of enzymes that catalyze the same reaction?

They are synthesized by pro-enzymes. Signup and view all the answers

Study Notes

Enzymes Overview

Enzymes are proteins that act as catalysts, accelerating biochemical reactions without being consumed.

Structure of Enzymes

Enzymes are linear amino acid chains folded into a three-dimensional structure.
The amino acid sequence dictates the enzyme's structure and its catalytic function.
The active site includes the catalytic site and binding sites, crucial for substrate orientation and reaction activity.

Factors Influencing Enzyme Activity

Reaction rates are affected by:
- Concentrations of substrates, products, coenzymes, and cofactors.
- Temperature and pH levels.
- Presence of activators, inhibitors, and inactivators.

Substrate Concentration Effect

Increasing substrate concentration boosts reaction rates until enzyme saturation occurs, where further increases have no effect due to all active sites being occupied.

Enzyme Concentration Effect

Similar to substrate concentration, increasing enzyme levels increases reaction rates until saturation limits the rate.

Temperature Influence

Higher temperatures enhance enzyme activity until the enzyme denatures, after which activity declines.

pH Influence

Each enzyme has an optimal pH for maximum activity; deviation can lead to denaturation, typically illustrated by a bell-shaped curve.

Activators and Inhibitors

Activators enhance enzyme activity by binding to the enzyme.
Inhibitors reduce activity and can be involved in allosteric regulation.

Classification of Enzymes

Enzymes are categorized by the type of reactions they catalyze.

Enzyme Classes

Oxido-reductases: Catalyze oxidation-reduction reactions.
Transferases: Facilitate group transfers.
Hydrolases: Cleave bonds with water addition.
Lyases: Break bonds without water addition.
Isomerases: Catalyze racemization of isomers.
Ligases: Form bonds using energy from compounds like ATP.

Coenzymes and Prosthetic Groups

Coenzymes: Nonprotein compounds essential for enzyme functionality, often reversible.
Prosthetic groups: Nonprotein elements permanently attached to proteins, functioning as irreversibly bound coenzymes.

Coenzymes in Specific Reactions

Oxido-reductases:
- NAD+/NADH, NADP+/NADPH, FAD/FADH2, Cu2+/Cu+.
Ligases:
- ATP, Biotin for enzymes like Pyruvate Carboxylase.
Transferases:
- ATP/ADP for kinases, Pyridoxal phosphate for aminotransferases.

Enzyme Distribution

Enzymes are localized within cells and tissues based on reaction requirements, e.g., hydrolases in lysosomes, peroxidases in peroxisomes, and DNA polymerases in nuclei.

Variability in Enzymes

Enzymes that catalyze the same reaction can exist in different forms, often synthesized from pro-enzymes.

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Description

This quiz explores the classification and mechanism of action of enzymes. Test your knowledge about what enzymes are, their structural properties, and their role as catalysts in biochemical reactions. Suitable for students studying biochemistry or related fields.