Small molecule

Small Molecule

A representation of a small molecule

A small molecule is a low molecular weight organic compound that may regulate a biological process, with a size on the order of 1 nm. In the context of biochemistry, small molecules can have a variety of roles, including as cell signaling molecules, as tools in molecular biology, as drugs in medicine, and in many other roles.

Small molecules are distinct from biopolymers such as nucleic acids, proteins, and polysaccharides, which are composed of repeating monomeric units. Small molecules can be natural, such as secondary metabolites, or synthetic, such as pharmaceuticals.

Characteristics

Small molecules typically have a molecular weight of less than 900 daltons. This allows them to rapidly diffuse across cell membranes, which is a critical property for their function as drugs and signaling molecules.

Natural Small Molecules

Natural small molecules include metabolites and secondary metabolites. Metabolites are intermediates and products of metabolism, while secondary metabolites are not directly involved in the normal growth, development, or reproduction of an organism. Examples include alkaloids, terpenoids, and flavonoids.

Synthetic Small Molecules

Synthetic small molecules are often designed to interact with specific biological targets to modulate their activity. These include many pharmaceutical drugs, which are used to treat diseases by interacting with enzymes, receptors, or ion channels.

Applications

In Medicine

In medicine, small molecules are used as therapeutic agents. They can be designed to interact with specific biological targets to treat diseases. For example, aspirin is a small molecule that inhibits the enzyme cyclooxygenase, reducing inflammation and pain.

In Research

Small molecules are also used as tools in molecular biology and biochemistry to study biological processes. They can be used to inhibit or activate specific proteins, allowing researchers to dissect complex signaling pathways.

Related Pages

• Biochemistry
• Pharmacology
• Metabolism
• Drug discovery