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AAT Bioquest

How does an enzyme catalyst work?

Posted July 25, 2024


Answer

An enzyme has several cavities on its outer surface. These cavities, which are the enzyme’s active sites, contain functional groups such as -COOH and -SH. The substrate, which has a complementary charge to the enzyme, fits into these cavities just like a key fits into a lock. When the substrate binds to the enzyme at its active site, the interaction forms an enzyme-substrate complex. The active groups within the active site facilitate the decomposition of this complex, leading to the formation of the product.

This process occurs in two steps:

  1. Combination of enzyme and reactant - The enzyme (E) binds with the reactant or substrate (R) to form an enzyme-substrate complex (ER).
  2. Disintegration of the complex to yield the product - The enzyme-substrate complex (ER) breaks down to release the product (P) and regenerate the enzyme (E). In a catalysis reaction, the enzyme acts as a catalyst by forming a temporary complex with the substrate, which then decomposes to produce the final product, allowing the enzyme to be reused in subsequent reactions.
Additional resources

Enzyme promiscuity: mechanism and applications

Enzymes

Amplite® Fluorimetric Coenzyme A Quantitation Kit *Green Fluorescence*