UGT2B7 is a phase II metabolism

Metabolism

Metabolism is the set of chemical reactions that happen in the cells of living organisms to sustain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories...

 isoenzyme

Isozyme

Isozymes are enzymes that differ in amino acid sequence but catalyze the same chemical reaction. These enzymes usually display different kinetic parameters Isozymes (also known as isoenzymes) are enzymes that differ in amino acid sequence but catalyze the same chemical reaction. These enzymes...

 found to be active in the liver

Liver

The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...

, kidney

Kidney

The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...

s, epithelial cells

Epithelium

Epithelium is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. Epithelial tissues line the cavities and surfaces of structures throughout the body, and also form many glands. Functions of epithelial cells include secretion, selective...

 of the lower gastrointestinal tract

Gastrointestinal tract

The human gastrointestinal tract refers to the stomach and intestine, and sometimes to all the structures from the mouth to the anus. ....

 and also has been reported in the brain

Brain

The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...

. In humans, UDP-Glucuronosyltransferase-2B7 is encoded by the UGT2B7 gene

Gene

A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

.

Function

The UGTs serve a major role in the conjugation and subsequent elimination of potentially toxic xenobiotic

Xenobiotic

A xenobiotic is a chemical which is found in an organism but which is not normally produced or expected to be present in it. It can also cover substances which are present in much higher concentrations than are usual...

s and endogenous compounds. UGT2B7 has unique specificity for 3,4-catechol estrogen

Estrogen

Estrogens , oestrogens , or œstrogens, are a group of compounds named for their importance in the estrous cycle of humans and other animals. They are the primary female sex hormones. Natural estrogens are steroid hormones, while some synthetic ones are non-steroidal...

s and estriol

Estriol

Estriol is one of the three main estrogens produced by the human body.-Synthesis:Estriol is only produced in significant amounts during pregnancy as it is made by the placenta from 16-Hydroxydehydroepiandrosterone sulfate , an androgen steroid made in the fetal liver and adrenal glands.The human...

, suggesting that it may play an important role in regulating the level and activity of these potent estrogen metabolites.

This enzyme is located on the endoplasmic reticulum

Endoplasmic reticulum

The endoplasmic reticulum is an organelle of cells in eukaryotic organisms that forms an interconnected network of tubules, vesicles, and cisternae...

 and nuclear membrane

Nuclear envelope

A nuclear envelope is a double lipid bilayer that encloses the genetic material in eukaryotic cells. The nuclear envelope also serves as the physical barrier, separating the contents of the nucleus from the cytosol...

s of cells. Its function is to catalyse

Catalysis

Catalysis is the change in rate of a chemical reaction due to the participation of a substance called a catalyst. Unlike other reagents that participate in the chemical reaction, a catalyst is not consumed by the reaction itself. A catalyst may participate in multiple chemical transformations....

 the conjugation of a wide variety of lipophilic aglycon substrates with glucuronic acid

Glucuronic acid

Glucuronic acid is a carboxylic acid. Its structure is similar to that of glucose. However, glucuronic acid's sixth carbon is oxidized to a carboxylic acid...

, using uridine diphosphate glucuronic acid

Uridine diphosphate glucuronic acid

UDP glucuronic acid is a sugar used in the creation of polysaccharides and is an intermediate in the biosynthesis of ascorbic acid ....

.

Together with UGT2B4

UGT2B4

UDP glucuronosyltransferase 2 family, polypeptide B4, also known as UGT2B4, is an enzyme that in humans is encoded by the UGT2B4 gene.- Function :...

, UGT2B7 is capable of glucosidation of hyodesoxycholic acid in the liver, but, unlike the 2B4 isoform, 2B7 is also able to glucuronidate various steroid hormones (androsterone

Androsterone

Androsterone is a steroid hormone with weak androgenic activity. It is made in the liver from the metabolism of testosterone. Its beta-isomer is Epiandrosterone.-History:...

, epitestosterone

Epitestosterone

Epitestosterone is a natural steroid, an inactive epimer of the hormone testosterone. Structurally, it differs from testosterone only in the configuration at the OH-bearing carbon, C17...

) and fatty acids. It is also able to conjugate major classes of drugs such as analgesics (morphine

Morphine

Morphine is a potent opiate analgesic medication and is considered to be the prototypical opioid. It was first isolated in 1804 by Friedrich Sertürner, first distributed by same in 1817, and first commercially sold by Merck in 1827, which at the time was a single small chemists' shop. It was more...

), carboxylic nonsteroidal anti-inflammatory drugs (ketoprofen

Ketoprofen

Ketoprofen, 2--propionic acid is one of the propionic acid class of non-steroidal anti-inflammatory drug with analgesic and antipyretic effects...

), and anticarcinogens (all-trans retinoic acid

Retinoic acid

Retinoic acid is a metabolite of vitamin A that mediates the functions of vitamin A required for growth and development. Retinoic acid is required in chordate animals which includes all higher animals from fishes to humans...

). UGT2B7 is the major enzyme isoform for the metabolism of morphine

Morphine

Morphine is a potent opiate analgesic medication and is considered to be the prototypical opioid. It was first isolated in 1804 by Friedrich Sertürner, first distributed by same in 1817, and first commercially sold by Merck in 1827, which at the time was a single small chemists' shop. It was more...

 to the main metabolites, morphine-3-glucuronide

Morphine-3-glucuronide

Morphine-3-glucuronide is a metabolite of morphine produced by UGT2B7. It is not active as an opioid agonist, but does have some action as a convulsant, which does not appear to be mediated through opioid receptors; it is mediated by GABA/glycinergic system...

 (M3G) which has no analgesic effect and morphine-6-glucuronide

Morphine-6-glucuronide

Morphine-6-glucuronide is a major active metabolite of morphine, and as such is the molecule responsible for much of the pain-relieving effects of morphine . M6G is formed from morphine by the enzyme UDP-Glucuronosyltransferase-2B7...

(M6G),, which is more potent analgesic than morphine. As a consequence, altered UGT2B7 activity can significantly affect both the effectiveness and side-effects of morphine, as well as some related opiate drugs.