Biochemistry: Classes of Enzymes

Study Notes

Classes of Enzymes

Oxidoreductases: Facilitate oxidation-reduction reactions critical in metabolic pathways.
Transferases: Catalyze the transfer of functional groups between molecules, playing a role in various biochemical processes.
Hydrolases: Enzymes that catalyze hydrolysis, breaking down compounds by adding water.
Lyases: Specialize in the addition or removal of groups such as water, ammonia, or carbon dioxide from substrates.
Isomerases: Enzymes that catalyze isomerization reactions, leading to structural rearrangements within molecules.
Ligases: Catalysts for synthetic reactions where two molecules are bonded together, often using ATP for energy.

Properties of Enzymes

Enzymes are primarily proteins, although some RNA molecules have enzymatic functions.
Each enzyme has a unique tertiary structure and conformation, essential for catalysis.
The functional unit called holoenzyme consists of an apoenzyme (protein part) and a coenzyme (organic non-protein part).

Classification of Enzymes

Each enzyme class contains sub-classes and further subdivisions.
Unique Enzyme Commission (E.C.) numbers consist of four digits, designating class, sub-class, sub-sub class, and individual enzyme.
Enzyme names reflect substrate, coenzyme (if applicable), and type of catalytic reaction.
Complex IUB naming conventions are not widely adopted; trivial names and E.C. numbers are commonly used for simplicity.

Genetic Engineering and Modified Enzymes

Advances in biotechnology enable enzyme modification for enhanced catalytic performance under various conditions.
Modified enzymes hold significant potential for applications in medicine and industry.

Hybrid Enzymes

Gene rearrangement can lead to the production of fusion proteins, such as hybrid enzymes that combine activities of glucanase and cellulase for improved hydrolysis of barley β-glucans during beer production.

Site-directed Mutagenesis

This technique allows for specific mutations within a DNA molecule to introduce desired amino acids into an enzyme.
Utilized to produce enzymes with tailored characteristics, exemplified by tissue plasminogen activator used for clot lysis in myocardial infarction.

Description

This quiz covers the various classes of enzymes, including oxidoreductases, transferases, hydrolases, lyases, isomerases, and ligases. It also explores key properties of enzymes, their structures, and functions in biochemical reactions. Test your knowledge on enzyme classification and characteristics!