Substrate (chemistry)
Introduction
In the field of chemistry, a substrate is typically the chemical species being observed, which reacts with a reagent. This term is highly context-dependent. In particular, in biochemistry, the substrate is usually a molecule upon which an enzyme acts.
Definition and Contexts
In chemistry, a substrate is a molecule acted upon by an enzyme. This definition is broad and could include any molecules that are chemically altered by a catalyst. In surface science, it refers to the solid used as a basis for a reaction. In spectroscopy, the term is used to describe the material onto which a sample is deposited for measurement.
Biochemistry
In biochemistry, the substrate is the molecule upon which an enzyme acts. Enzymes catalyze chemical reactions involving the substrate(s). In the case of a single substrate, the substrate binds with the enzyme active site, and an enzyme-substrate complex is formed. The substrate is transformed into one or more products, which are then released from the active site. The active site is now free to accept another substrate molecule. In the case of more than one substrate, these may bind in a particular order to the active site, before reacting together to produce products.
Surface Science
In surface science, a substrate is the material on the surface of which an adsorbate is adsorbed. The substrate can affect the properties of the adsorbate, such as the electronic, vibrational, and translational states. The term is also used to describe the bulk material in the field of thin film deposition.
Spectroscopy
In spectroscopy, a substrate is the material onto which a sample is deposited for measurement. The interaction of the substrate with the sample can affect the spectroscopic measurement, so the choice of an appropriate substrate is necessary to ensure accurate measurements.