Angiotensin
Horseradish Peroxidase
Hyaluronidase
Urokinase Human
Definition: Enzymes are biological catalysts that accelerate chemical reactions in living organisms. They are typically proteins, although some RNA molecules also exhibit catalytic activity (ribozymes).
Classification: Enzymes are classified based on the type of reaction they catalyze:
Key Biological Properties: Enzymes exhibit high specificity for their substrates and operate under mild conditions of temperature and pH. They are highly efficient, often increasing reaction rates by millions of times.
Expression Patterns: Enzyme expression is tightly regulated and can vary between different tissues and developmental stages.
Tissue Distribution: Enzymes are distributed throughout the body, with specific enzymes localized to particular tissues or cellular compartments. For example, digestive enzymes are abundant in the gastrointestinal tract, while metabolic enzymes are prevalent in the liver.
Primary Biological Functions: Enzymes play crucial roles in various biological processes, including metabolism, DNA replication, and repair, signal transduction, and cellular respiration.
Role in Immune Responses: Enzymes are involved in the immune response by processing antigens, generating reactive oxygen species to kill pathogens, and modulating signaling pathways.
Pathogen Recognition: Enzymes such as lysozymes can recognize and break down bacterial cell walls, aiding in pathogen elimination.
Mechanisms with Other Molecules and Cells: Enzymes interact with substrates through their active sites, forming enzyme-substrate complexes. This interaction lowers the activation energy required for the reaction.
Binding Partners: Enzymes often require cofactors (metal ions or organic molecules) or coenzymes (vitamins or their derivatives) to function properly.
Downstream Signaling Cascades: Enzymes can initiate or propagate signaling cascades by modifying signaling molecules, such as phosphorylation by kinases or dephosphorylation by phosphatases.
Regulatory Mechanisms: Enzyme activity is regulated at multiple levels, including gene expression, post-translational modifications, and feedback inhibition.
Transcriptional Regulation: The expression of enzyme-coding genes can be upregulated or downregulated in response to cellular signals and environmental conditions.
Post-Translational Modifications: Enzymes can be activated or inactivated by modifications such as phosphorylation, acetylation, or ubiquitination.
Biomedical Research: Enzymes are used as tools in molecular biology for DNA manipulation, such as restriction enzymes and DNA polymerases.
Diagnostic Tools: Enzymes are employed in diagnostic assays, such as glucose oxidase in blood glucose meters.
Therapeutic Strategies: Enzyme replacement therapy is used to treat enzyme deficiency disorders, and enzymes are being explored as drug targets for various diseases.
Role Throughout the Life Cycle: Enzymes are essential at all stages of life, from development to aging. They regulate developmental processes, maintain cellular homeostasis, and repair damaged tissues.
Development: Enzymes control the synthesis and degradation of biomolecules, guiding the growth and differentiation of cells.
Aging and Disease: Enzyme activity can decline with age, contributing to the aging process and the development of age-related diseases. Enzymes are also implicated in various diseases, including cancer, neurodegenerative disorders, and metabolic syndromes.