An adaptive enzyme or inducible enzyme is an
enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products ...
that is
expressed only under conditions in which it is clearly of adaptive value, as opposed to a
constitutive enzyme which is produced all the time.
The inducible enzyme is used for the breaking-down of things in the cell. It is also a part of the Operon Model, which illustrates a way for genes to turn "on" and "off".
The inducer causes the gene to turn on (controlled by the amount of reactant which turns the gene on). Then there's the repressor protein that turns genes off. The inducer can remove this repressor, turning genes back on. The operator is a section of DNA where the repressor binds to shut off certain genes; the promoter is the section of DNA where the
RNA polymerase
In molecular biology, RNA polymerase (abbreviated RNAP or RNApol), or more specifically DNA-directed/dependent RNA polymerase (DdRP), is an enzyme that synthesizes RNA from a DNA template.
Using the enzyme helicase, RNAP locally opens th ...
binds. Lastly, the regulatory gene is the gene for the repressor protein.
An example of inducible enzyme is
COX-2
Prostaglandin-endoperoxide synthase 2 (prostaglandin G/H synthase and cyclooxygenase) (The HUGO official symbol is PTGS2; HGNC ID, HGNC:9605), also known as cyclooxygenase-2 or COX-2, is an enzyme that in humans is encoded by the ''PTGS2'' gene ...
which is synthesized in
macrophages
Macrophages (abbreviated as M φ, MΦ or MP) ( el, large eaters, from Greek ''μακρός'' (') = large, ''φαγεῖν'' (') = to eat) are a type of white blood cell of the immune system that engulfs and digests pathogens, such as cancer ce ...
to produce
prostaglandin E2 while the
constitutive enzyme COX-1
Cyclooxygenase 1 (COX-1), also known as prostaglandin G/H synthase 1, prostaglandin-endoperoxide synthase 1 or prostaglandin H2 synthase 1, is an enzyme that in humans is encoded by the ''PTGS1'' gene. In humans it is one of two cyclooxygenases.
...
(another isozyme in
COX
Cox may refer to:
* Cox (surname), including people with the name
Companies
* Cox Enterprises, a media and communications company
** Cox Communications, cable provider
** Cox Media Group, a company that owns television and radio stations
** ...
family) is always produced in variety of organs in body (like stomach).
References
Enzymes
{{Enzyme-stub