A structural analog (analogue in modern traditional English;
Commonwealth English
The use of the English language in current and former member countries of the Commonwealth of Nations was largely inherited from British colonisation, with some exceptions. English serves as the medium of inter-Commonwealth relations.
Many ...
), 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 a ...
similar to that of another compound, but differing from it in respect to a certain component.
It can differ in one or more
atom
Every atom is composed of a nucleus and one or more electrons bound to the nucleus. The nucleus is made of one or more protons and a number of neutrons. Only the most common variety of hydrogen has no neutrons.
Every solid, liquid, gas, a ...
s,
functional group
In organic chemistry, a functional group is a substituent or moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions regardless of the 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 b ...
, either a large series of structural analogs of an initial
lead compound 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 Crum-Brown and Fraser in 1865.
The analysis of SAR enables the determination o ...
study
or a database is
screened
A projection screen is an installation consisting of a surface and a support structure used for displaying a projected image for the view of an audience. Projection screens may be permanently installed, as in a movie theater; painted on the w ...
for structural analogs of a
lead compound.
Chemical analogues of
illegal drugs 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. D ...
s. Because of this, the United States passed the
Federal Analogue Act 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 synapse. The cell receiving the signal, any main body part or target cell, may be another neuron, but could also be a gland or muscle cell.
Neu ...
, typically a
drug
A drug is any chemical substance that causes a change in an organism's physiology or psychology when consumed. Drugs are typically distinguished from food and substances that provide nutritional support. Consumption of drugs can be via inhala ...
. Some examples include:
*
Catecholamine analogue
*
Serotonin analogue
*
GABA analogue
A GABA analogue is a compound which is an analogue or derivative of the neurotransmitter gamma-Aminobutyric acid (GABA) (the IUPAC of which is 4-aminobutanoic acid).
Many GABA analogues are used as drugs, especially as anticonvulsants, sedative ...
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 repl ...
*
Federal Analogue Act, a United States bill banning chemical analogues of illegal drugs
*
Functional analog, compounds with similar physical, chemical, biochemical, or pharmacological properties
*
Homolog, a compound of a series differing only by repeated units
*
Transition state analog
References
{{Reflist
External links
Analoging in ChEMBL, DrugBank and the Connectivity Map– a free web-service for finding structural analogs in
ChEMBL
ChEMBL or ChEMBLdb is a manually curated chemical database of bioactive molecules with drug-like properties.
It is maintained by the European Bioinformatics Institute (EBI), of the European Molecular Biology Laboratory (EMBL), based at the Well ...
,
DrugBank, and the Connectivity Map
Chemical nomenclature