Ribbon diagram of a monomer of human MAO-A, with FAD and clorgiline bound, oriented as if attached to the outer membrane of a mitochondrion. A monomer (from Greek mono "one" and meros "part" is a small Molecule that may become chemically bonded to other In Biochemistry, flavin adenine dinucleotide ( FAD) is a Redox cofactor involved in several important reactions in Metabolism. Clorgiline ( INN) or clorgyline is an inhibitor of Monoamine oxidase type A structurally related to Pargyline. The outer membrane refers to the outside membranes of Gram-negative bacteria, the Chloroplast, or the Mitochondria. In Cell biology, a mitochondrion (plural mitochondria) is a membrane-enclosed Organelle found in most eukaryotic cells. From PDB 2BXS. The Protein Data Bank ( PDB) is a repository for 3-D structural data of Proteins and Nucleic acids These data typically obtained by X-ray crystallography
monoamine oxidase A
Identifiers
Symbol	MAOA
Entrez	4128
HUGO	6833
OMIM	309850
RefSeq	NM_000240
UniProt	P21397
Other data
EC number	1.4.3.4
Locus	Chr. X p11.4-p11.3

Cartoon diagram of human MAO-B. Monoamine oxidase A, also known as MAOA, is a human Gene. This gene encodes Monoamine oxidase A, an enzyme that degrades amine neurotransmitters such Monoamine oxidase A, also known as MAOA, is a human Gene. This gene encodes Monoamine oxidase A, an enzyme that degrades amine neurotransmitters such The Entrez Global Query Cross-Database Search System is a powerful Federated search engine or Web portal that allows users to search many discrete Health sciences The Human Genome Organisation (HUGO is an organization involved in the Human Genome Project, a project about mapping the human genome The Mendelian Inheritance in Man project is a Database that catalogues all the known Diseases with a genetic component, and—when possible—links them The National Center for Biotechnology Information ( NCBI) is part of the United States National Library of Medicine (NLM a branch of the National Institutes Swiss-Prot is a manually curated Biological database of Protein sequences This article is about the Enzyme Commission codes For the European Commission system for coding chemicals see EC-No. In the fields of Genetics and Evolutionary computation, a locus (plural loci) is a fixed position on a Chromosome such as the position of a The X chromosome is one of the two sex-determining Chromosomes in many animal species including mammals (the other is the Y chromosome) From PDB 1GOS. The Protein Data Bank ( PDB) is a repository for 3-D structural data of Proteins and Nucleic acids These data typically obtained by X-ray crystallography
monoamine oxidase B
Identifiers
Symbol	MAOB
Entrez	4129
HUGO	6834
OMIM	309860
RefSeq	NM_000898
UniProt	P27338
Other data
EC number	1.4.3.4
Locus	Chr. X p11.4-p11.3

Monoamine oxidases (singular abbreviation MAO) (EC 1.4.3.4) are enzymes that catalyze the oxidation of monoamines. The Entrez Global Query Cross-Database Search System is a powerful Federated search engine or Web portal that allows users to search many discrete Health sciences The Human Genome Organisation (HUGO is an organization involved in the Human Genome Project, a project about mapping the human genome The Mendelian Inheritance in Man project is a Database that catalogues all the known Diseases with a genetic component, and—when possible—links them The National Center for Biotechnology Information ( NCBI) is part of the United States National Library of Medicine (NLM a branch of the National Institutes Swiss-Prot is a manually curated Biological database of Protein sequences This article is about the Enzyme Commission codes For the European Commission system for coding chemicals see EC-No. In the fields of Genetics and Evolutionary computation, a locus (plural loci) is a fixed position on a Chromosome such as the position of a The X chromosome is one of the two sex-determining Chromosomes in many animal species including mammals (the other is the Y chromosome) This article is about the Enzyme Commission codes For the European Commission system for coding chemicals see EC-No. Enzymes are Biomolecules that catalyze ( ie increase the rates of Chemical reactions Almost all enzymes are Proteins Catalysis is the process in which the rate of a Chemical reaction is increased by means of a Chemical substance known as a catalyst Redox (shorthand for reduction-oxidation reaction describes all Chemical reactions in which atoms have their Oxidation number ( Oxidation state Monoamine neurotransmitters are Neurotransmitters and Neuromodulators that contain one Amino group that is connected to an aromatic ring by a They are found bound to the outer membrane of mitochondria in most cell types in the body. In Cell biology, a mitochondrion (plural mitochondria) is a membrane-enclosed Organelle found in most eukaryotic cells. The enzyme was discovered by Mary Hare in the liver, and received the name of tyramine oxidase. The liver is a vital organ in the human body and is present in Vertebrates and some other animals ^[1] They belong to protein family of flavin containing amine oxidoreductases. A protein family is a group of Evolutionarily related Proteins and is often nearly synonymous with Gene family. Flavin containing amine oxidoreductases are a family of various Amine oxidases including maize Polyamine oxidase (PAO L- Amino acid oxidases (LAO

Locations of MAO-A and MAO-B

In humans there are two types of MAO: MAO-A and MAO-B. Monoamine oxidase A is an Isozyme of Monoamine oxidase. It preferentially deaminates Norepinephrine (noradrenaline and serotonin Monoamine oxidase B, also known as MAOB, is a human Gene.

• Both are found in neurons and astroglia. Neurons (ˈnjuːɹɒn also known as neurones and nerve cells) are responsive cells in the Nervous system that process and transmit information Astrocytes (also known collectively as astroglia) are characteristic star-shaped glial cells in the Brain and Spinal cord.
• Outside the central nervous system:
  • MAO-A is also found in the liver, gastrointestinal tract and placenta. In Vertebrates the central nervous system ( CNS) is the part of the Nervous system which is enclosed in the Meninges. The liver is a vital organ in the human body and is present in Vertebrates and some other animals The placenta is an Ephemeral organ present in placental Vertebrates, such as Eutherial Mammals and Sharks during Gestation
  • MAO-B is mostly found in blood platelets. Blood is a specialized Bodily fluid that delivers necessary substances to the body's cells ��such as nutrients and oxygen—and transports Waste products Platelets, or Thrombocytes, are small cytoplasmic bodies derived from cells They circulate in the Blood of Mammals and are involved

Function

Monoamine oxidases catalyze the oxidative deamination of monoamines. Oxidative deamination is a form of Deamination that generates Oxoacids in the Liver. Oxygen is used to remove an amine group from a molecule, resulting in the corresponding aldehyde and ammonia. Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the Amines are Organic compounds and Functional groups that contain a basic Nitrogen Atom with a Lone pair. An aldehyde is an organic compound containing a terminal Carbonyl group. Ammonia is a compound with the formula N[[hydrogen H3]] It is normally encountered as a Gas with a characteristic pungent Odor The general form of the catalyzed reaction (with R denoting an arbitrary group) is

Monoamine oxidases contain the covalently-bound cofactor FAD and are thus classified as flavoproteins. An oxidase is any Enzyme that catalyzes an oxidation/reduction reaction involving molecular Oxygen (O2 as the electron acceptor A cofactor is a non-protein Chemical compound that is bound (either tightly or loosely to an Enzyme and is required for Catalysis. In Biochemistry, flavin adenine dinucleotide ( FAD) is a Redox cofactor involved in several important reactions in Metabolism. Flavoproteins are Proteins that contain a Nucleic acid derivative of Riboflavin: the Flavin adenine dinucleotide (FAD or Flavin mononucleotide

Subtype Specificities

MAO-A is particularly important in the catabolism of monoamines ingested in food. Both MAOs are also vital to the inactivation of monoaminergic neurotransmitters, for which they display different specificities. See Chemical synapse for an introduction to concepts and terminology used in this article Enzymes are Biomolecules that catalyze ( ie increase the rates of Chemical reactions Almost all enzymes are Proteins

• Serotonin, norepinephrine (noradrenaline), and epinephrine (adrenaline) are mainly broken down by MAO-A. Serotonin (ˌsɛrəˈtoʊnən ( 5-hydroxytryptamine, or 5-HT) is a Monoamine Neurotransmitter synthesized in serotonergic Neurons Norepinephrine ( INN) (abbreviated norepi or NE) or noradrenaline ( BAN) (abbreviated NA or NAd) is a
• Phenethylamine is broken down by MAO-B. Phenethylamine, or β -phenylethylamine or 2-phenylethylamine is an Alkaloid and Monoamine.
• Both forms break down dopamine. Dopamine is a Hormone and Neurotransmitter occurring in a wide variety of animals including both vertebrates and invertebrates

Disorders resulting from MAO dysfunction

Because of the vital role that MAOs play in the inactivation of neurotransmitters, MAO dysfunction (too much/too little MAO activity) is thought to be responsible for a number of neurological disorders. For example, unusually high or low levels of MAOs in the body have been associated with depression, substance abuse, attention deficit disorder, and irregular sexual maturation. Major depressive disorder, also known as major depression, unipolar depression, unipolar disorder, clinical depression, or simply depression Substance abuse is the overindulgence in and dependence of a Drug or other chemical leading to effects that are detrimental to the individual's physical and mental health ADHD predominantly inattentive (ADHD-I is one of the three subtypes of Attention-deficit hyperactivity disorder (ADHD Monoamine oxidase inhibitors are one of the major classes of drug prescribed for the treatment of depression, although they are last line treatment due to risk of the drug's interaction with diet or other drugs. Monoamine oxidase inhibitors ( MAOIs) are a class of powerful antidepressant drugs prescribed for the treatment of depression. Excessive levels of catecholamines (epinephrine, norepinephrine, and dopamine) may lead to a hypertensive crisis, and excessive levels of serotonin may lead to serotonin syndrome. Norepinephrine ( INN) (abbreviated norepi or NE) or noradrenaline ( BAN) (abbreviated NA or NAd) is a Dopamine is a Hormone and Neurotransmitter occurring in a wide variety of animals including both vertebrates and invertebrates Serotonin (ˌsɛrəˈtoʊnən ( 5-hydroxytryptamine, or 5-HT) is a Monoamine Neurotransmitter synthesized in serotonergic Neurons Serotonin syndrome is a potentially life-threatening adverse drug reaction that may occur following therapeutic drug use inadvertent interactions between drugs or the recreational

PET research has shown that MAO is also heavily depleted by use of tobacco cigarettes. Positron emission tomography ( PET) is a Nuclear medicine imaging technique which produces a three-dimensional image or map of functional processes in the Tobacco is an Agricultural product recognized as an addictive drug processed from the fresh Leaves of plants in the genus Nicotiana. ^[2]

Genetics

The genes encoding MAO-A and MAO-B are located side-by-side on the short arm of the X chromosome, and have about 70% sequence similarity. History See also History of genetics The existence of genes was first suggested by Gregor Mendel (1822-1884 who in the 1860s studied inheritance The X chromosome is one of the two sex-determining Chromosomes in many animal species including mammals (the other is the Y chromosome) Rare mutations in the gene are associated with Brunner syndrome. A rare 5 males in one large extended family Genetic disorder with a Mutation in the MAOA gene

A study reported in Science in August 2002 based on the Dunedin cohort concluded that maltreated children with a low-activity polymorphism in the promoter region of the MAO-A gene were more likely to develop antisocial conduct disorders than maltreated children with the high-activity variant. Science is the Academic journal of the American Association for the Advancement of Science and is considered one of the world's most prestigious Scientific The Dunedin Multidisciplinary Health and Development Study (often referred to as the Dunedin Longitudinal Study) is a long-running Cohort study of 1037 people born In Biology, a promoter is a region of DNA that facilitates the transcription of a particular Gene. Conduct disorder is a psychiatric category to describe a pattern of repetitive behavior where the rights of others or the current Social norms are violated ^[3] Out of the 442 total males in the study (maltreated or not), 37% had the low activity variant. Of the 13 maltreated males with low MAO-A activity, 11 had been assessed as exhibiting adolescent conduct disorder and 4 were convicted for violent offenses. The suggested mechanism for this effect is the decreased ability of those with low MAO-A activity to quickly degrade norepinephrine, the synaptic neurotransmitter involved in sympathetic arousal and rage. The Sympathetic Nervous System ( SNS) is a branch of the Autonomic nervous system along with the Enteric nervous system and Parasympathetic nervous This is alleged to provide direct support for the idea that genetic susceptibility to disease is not determined at birth, but varies with exposure to environmental influences. Note however that most of those with conduct disorder or convictions did not have low activity of MAO-A; maltreatment was found to caused stronger predisposition for antisocial behavior than differences in MAO-A activity.

Research also uncovered a possible link between predisposition to novelty seeking and a genotype of the MAO-A gene. Neophilia is defined as a love of novelty and new things A neophiliac or Neophile is an individual who is unusually accepting of new things and excited by novelty The genotype is the genetic constitution of a cell an organism or an individual (i ^[4]

In 2006, a New Zealand researcher, Dr Rod Lea said that a particular variant (or genotype) was over-represented in Māori, a Warrior gene. The genotype is the genetic constitution of a cell an organism or an individual (i This article discusses the Māori people of New Zealand For their language see Māori language, and for other meanings see Māori (disambiguation. A version of the primate Monoamine oxidase -A gene has been referred to as the warrior gene, initially in monkeys then in humans This supported earlier studies finding different proportions of variants in different ethnic groups. This is the case for many genetic variants, with 33% White/Non-Hispanic, 61% Asian/Pacific Islanders having the low-activity MAO-A promoter variant. In Biology, a promoter is a region of DNA that facilitates the transcription of a particular Gene. ^[5]

See also

• Monoamine oxidase inhibitor
• Genetics and violence
• Neophilia
• Warrior gene
• Brunner syndrome

References

External links

• MAO-B Structure at eurekalert.org
• Calculated orientations of Monoamine oxidases in membrane
• Monoamine oxidase (MAO) at bmc.uu.se
• Slides showing the effects of tobacco smoking on MAO at nida.nih.gov
• Foods to avoid when taking MAO inhibitors at lycaeum.org
• Information Hyperlinked Over Proteins -- MAO-A