Inhibition refers to the suppression or reduction of the activity or growth of microorganisms or biochemical reactions due to environmental conditions or specific inhibitory substances.
Explanation
In microbiology and biochemistry, inhibition describes processes that limit or prevent growth, metabolism or enzymatic activity. Microbial inhibition can result from physical factors such as temperature, pH or osmotic pressure, or from chemical agents like antibiotics, antiseptics and preservatives. Enzyme inhibition occurs when molecules interfere with substrate binding or catalytic action; competitive inhibitors bind the active site and compete with the substrate, while non‑competitive inhibitors bind allosteric sites and alter enzyme conformation. Selective culture media often contain inhibitory compounds to suppress unwanted organisms, allowing target species to grow. Measuring minimal inhibitory concentration (MIC) helps determine the lowest concentration of an antimicrobial that prevents visible growth, guiding antibiotic therapy. Understanding inhibition mechanisms supports development of treatments and helps maintain quality in food production and pharmaceuticals.
Examples and applications
Beta‑lactam antibiotics inhibit bacterial cell wall synthesis by binding penicillin‑binding proteins. Protease inhibitors used in antiretroviral therapy block viral proteases, preventing maturation of HIV particles. Sodium azide inhibits cytochrome c oxidase and is used in biochemical assays to halt oxidative phosphorylation. Selective media such as MacConkey agar use bile salts and crystal violet to inhibit Gram‑positive bacteria, allowing differentiation of Gram‑negative enteric organisms. In fermentation, weak acids like sorbic acid inhibit fungal contaminants to protect foods.
In summary, inhibition is a fundamental concept describing the intentional or environmental reduction of microbial growth or enzymatic activity. Through understanding inhibitory mechanisms, microbiologists can select appropriate antimicrobials, design selective media, and control spoilage.
Related Terms: Antimicrobial, Antibiotic, Enzyme, Competitive inhibition, MIC