What is enzyme-substrate specificity?

Enzyme-substrate specificity refers to the ability of an enzyme to selectively bind and catalyse a specific substrate.

Enzymes are biological catalysts that speed up chemical reactions in living organisms. They are highly specific, meaning they can only catalyse certain reactions. This specificity is due to the unique shape and structure of the enzyme, particularly the active site, which is the region where the substrate binds. The active site has a specific shape that fits perfectly with its substrate, much like a lock and key. This is known as the 'lock and key' model of enzyme action.

The specificity of an enzyme for its substrate is determined by the enzyme's structure, which is in turn determined by its amino acid sequence. The active site of an enzyme is a three-dimensional cavity formed by groups of amino acids that are far apart in the sequence but brought together in the folded protein. The shape and chemical environment of the active site allows it to bind to a specific substrate and catalyse its conversion to the product.

The enzyme-substrate specificity is crucial for the proper functioning of biological systems. It ensures that enzymes catalyse only the correct reactions, preventing unwanted side reactions that could be harmful to the cell. This specificity also allows for the regulation of metabolic pathways, as the activity of a specific enzyme can be increased or decreased to control the rate of a particular reaction.

In summary, enzyme-substrate specificity is a fundamental concept in biochemistry that describes the unique ability of enzymes to recognise, bind, and catalyse a specific substrate. This specificity is determined by the unique structure of the enzyme's active site and is crucial for the regulation of metabolic reactions in living organisms.