catalytic activity

Definition

Target type: molecularfunction

Catalysis of a biochemical reaction at physiological temperatures. In biologically catalyzed reactions, the reactants are known as substrates, and the catalysts are naturally occurring macromolecular substances known as enzymes. Enzymes possess specific binding sites for substrates, and are usually composed wholly or largely of protein, but RNA that has catalytic activity (ribozyme) is often also regarded as enzymatic. [GOC:vw, ISBN:0198506732]

Catalytic activity is a fundamental molecular function that describes the ability of a molecule, typically an enzyme, to accelerate a chemical reaction without being consumed in the process. This acceleration is achieved by lowering the activation energy of the reaction, which is the energy barrier that must be overcome for reactants to convert into products.

Enzymes, which are biological catalysts, typically bind to specific molecules called substrates and facilitate the formation of new chemical bonds or the breaking of existing ones. This process is highly specific, meaning each enzyme usually catalyzes a particular reaction involving a limited range of substrates.

The mechanism of catalysis involves several steps:

1. **Substrate binding:** The enzyme binds to the substrate(s) at a specific site called the active site.
2. **Formation of the enzyme-substrate complex:** The enzyme and substrate interact through non-covalent interactions, forming a temporary complex.
3. **Catalysis:** The enzyme facilitates the chemical transformation of the substrate(s) into product(s) through a series of steps that may involve conformational changes, proton transfer, or other chemical reactions.
4. **Product release:** The enzyme releases the product(s) and returns to its original state, ready to catalyze another reaction.

The catalytic activity of enzymes can be influenced by factors such as temperature, pH, substrate concentration, and the presence of inhibitors or activators.

Catalytic activity is essential for all living organisms, playing a crucial role in a wide range of cellular processes, including metabolism, DNA replication, protein synthesis, signal transduction, and defense against pathogens.'
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Proteins (12)

Compounds (277)