A structural analog, also known as a chemical analog or simply an analog, is a
compound having a
structure
A structure is an arrangement and organization of interrelated elements in a material object or system, or the object or system so organized. Material structures include man-made objects such as buildings and machines and natural objects such as ...
similar to that of another compound, but differing from it in respect to a certain component.
It can differ in one or more
atom
Atoms are the basic particles of the chemical elements. An atom consists of a atomic nucleus, nucleus of protons and generally neutrons, surrounded by an electromagnetically bound swarm of electrons. The chemical elements are distinguished fr ...
s,
functional group
In organic chemistry, a functional group is any substituent or moiety (chemistry), moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions r ...
s, or substructures, which are replaced with other atoms, groups, or substructures. A structural analog can be imagined to be formed, at least theoretically, from the other compound. Structural analogs are often
isoelectronic
Isoelectronicity is a phenomenon observed when two or more molecules have the same structure (positions and connectivities among atoms) and the same electronic configurations, but differ by what specific elements are at certain locations in th ...
.
Despite a high chemical similarity, structural analogs are not necessarily
functional analogs and can have very different physical, chemical, biochemical, or pharmacological properties.
In
drug discovery
In the fields of medicine, biotechnology, and pharmacology, drug discovery is the process by which new candidate medications are discovered.
Historically, drugs were discovered by identifying the active ingredient from traditional remedies or ...
, either a large series of structural analogs of an initial
lead compound
A lead compound (, i.e. a "leading" compound, not to be confused with various compounds of the metallic element lead) in drug discovery is a chemical compound that has pharmacological or biological activity likely to be therapeutically useful, but ...
are created and tested as part of a
structure–activity relationship
The structure–activity relationship (SAR) is the relationship between the chemical structure of a molecule and its biological activity. This idea was first presented by Alexander Crum Brown and Thomas Richard Fraser at least as early as 1868.
Th ...
study
or a database is
screened for structural analogs of a
lead compound
A lead compound (, i.e. a "leading" compound, not to be confused with various compounds of the metallic element lead) in drug discovery is a chemical compound that has pharmacological or biological activity likely to be therapeutically useful, but ...
.
Chemical analogues of
illegal drugs
Illegal may refer to:
Law
* Violation of law
** Crime
In ordinary language, a crime is an unlawful act punishable by a State (polity), state or other authority. The term ''crime'' does not, in modern criminal law, have any simple and uni ...
are developed and sold in order to circumvent laws. Such substances are often called
designer drug
A designer drug is a structural or functional analog of a controlled substance that has been designed to mimic the pharmacological effects of the original drug, while avoiding classification as illegal and/or detection in standard drug tests. ...
s. Because of this, the United States passed the
Federal Analogue Act
The Federal Analogue Act, , is a section of the United States Controlled Substances Act passed in 1986 which allows any chemical "substantially similar" to a controlled substance listed in Schedule I or II to be treated as if it were listed ...
in 1986. This bill banned the production of any chemical analogue of a
Schedule I or
Schedule II substance that has substantially similar pharmacological effects, with the intent of human consumption.
Examples
Neurotransmitter analog
A neurotransmitter analog is a structural analogue of a
neurotransmitter
A neurotransmitter is a signaling molecule secreted by a neuron to affect another cell across a Chemical synapse, synapse. The cell receiving the signal, or target cell, may be another neuron, but could also be a gland or muscle cell.
Neurotra ...
, typically a
drug
A drug is any chemical substance other than a nutrient or an essential dietary ingredient, which, when administered to a living organism, produces a biological effect. Consumption of drugs can be via insufflation (medicine), inhalation, drug i ...
. Some examples include:
*
Catecholamine analogue
*
GABA analogue
*
Serotonin analogue
Substituted tryptamines, or simply tryptamines, also known as serotonin analogues (i.e., 5-hydroxytryptamine analogues), are organic compounds which may be thought of as being derived from tryptamine itself. The molecular structures of all trypt ...
See also
*
Derivative (chemistry)
In chemistry, a derivative is a compound that is derived from a similar compound by a chemical reaction.
In the past, derivative also meant a compound that ''can be imagined to'' arise from another compound, if one atom or group of atoms is rep ...
*
Functional analog, compounds with similar physical, chemical, biochemical, or pharmacological properties
*
Homolog
In biology, homology is similarity in anatomical structures or genes between organisms of different taxa due to shared ancestry, ''regardless'' of current functional differences. Evolutionary biology explains homologous structures as retained her ...
, a compound of a series differing only by repeated units
*
Transition state analog
Transition state analogs (transition state analogues), are chemical compounds with a chemical structure that resembles the transition state of a substrate molecule in an enzyme-catalyzed chemical reaction. Enzymes interact with a substrate by mea ...
References
{{Reflist
External links
Analoging in ChEMBL, DrugBank and the Connectivity Map– a free web-service for finding structural analogs in
ChEMBL,
DrugBank
The DrugBank database is a comprehensive, freely accessible, online database containing information on drugs and drug targets created and maintained by the University of Alberta and The Metabolomics Innovation Centre located in Alberta, Canada. A ...
, and the Connectivity Map
Chemical nomenclature