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Gene Review

MAOB  -  monoamine oxidase B

Homo sapiens

Synonyms: MAO-B, Monoamine oxidase type B
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Disease relevance of MAOB


Psychiatry related information on MAOB


High impact information on MAOB

  • Here we show that targetted inactivation of MAOB in mice increases levels of PEA but not those of 5-HT, NE and DA, demonstrating a primary role for MAOB in the metabolism of PEA [11].
  • Increased stress response and beta-phenylethylamine in MAOB-deficient mice [11].
  • By subcloning a YAC with a 640 kilobases (kb) insert which spans the DXS7-MAOB interval we have generated a cosmid contig which extends 250 kb beyond the MAOB gene [12].
  • We propose that reduction of MAO B activity may synergize with nicotine to produce the diverse behavioural and epidemiological effects of smoking [13].
  • Mechanisms of bioactivation by MAO-B of MPTP to MPP+, concentration of MPP+ in neurons with a catecholamine uptake system, and vulnerability to cellular toxic effects of MPP+ are the basis for the specificity of MPTP targeting of nigrostriatal dopaminergic neurons [14].

Chemical compound and disease context of MAOB


Biological context of MAOB

  • The implications of fast acetylation, selective MAO inhibitors, types MAOA and MAOB, and measures of platelet MAO inhibition are discussed in this article [20].
  • Human MAOA and MAOB genes isolated from X chromosome-specific libraries span at least 60 kilobases, consist of 15 exons, and exhibit identical exon-intron organization [21].
  • Our results map the gene responsible for the disorder between the MAOB and DXS426, m27 beta and p58-1 loci, on the short arm of the X chromosome at Xp11.3, which suggest the possibility that the same gene is responsible for both primary retinal dysplasia and Norrie disease [22].
  • We have performed linkage analysis of the family using the L1.28, p58-1 and m27 beta probes, and DXS426 and MAOB associated microsatellites [22].
  • It has been shown from pulsed-field gel electrophoresis (PFGE) that the monoamine oxidase genes A and B (MAOA & MAOB) and DXS7 loci are physically very close [23].

Anatomical context of MAOB

  • Activities of both MAOA and MAOB were significantly increased in frontal cortex and caudate nucleus, two brain regions shown previously to be the site of functional and morphological alterations of astrocytes and increased concentrations of the acid metabolites of dopamine and serotonin [2].
  • In Northern blot analyses MAOA mRNA was expressed broadly in various parts of the canine brain, whereas MAOB mRNA was found only in specific brain regions, such as the hypothalamus, hippocampus, brain stem and olfactory bulb [24].
  • A monoclonal antibody was used to prepare immunoaffinity columns that efficiently bind monoamine oxidase B activity but not monoamine oxidase A activity from detergent extracts of human liver mitochondria [25].
  • Normal levels of MAO-A activities, as well as normal amounts and size of the MAO-A mRNA, were observed in cultured skin fibroblasts from these patients, and MAO-B activity in their platelets was normal [26].
  • However, the imidazoline binding domain was not detected in platelet membrane preparations containing amounts of MAO-B equivalent to those in the photolabeled liver membranes indicating that recognition of this domain is tissue-restricted [27].

Associations of MAOB with chemical compounds

  • Monoamine oxidases A and B [MAOA and MAOB; amine:oxygen oxidoreductase (deaminating) (flavin-containing), EC] play important roles in the metabolism of neuroactive, vasoactive amines and the Parkinsonism-producing neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) [21].
  • Exon 12 codes for the covalent FAD-binding-site and is the most conserved exon; the MAOA and MAOB exon 12 products share 93.9% peptide identity [21].
  • This 4.96 Mb region contains, among others, the genes for monoamine oxidase A (MAOA) and B (MAOB), which are involved in the oxidative deamination of several neurotransmitters, including dopamine and serotonin [28].
  • Exon 12 (bearing the codon for cysteine, which carries the covalently bound FAD cofactor) and exon 13 are highly conserved between human MAOA and MAOB genes (92% at the amino acid level) [29].
  • To understand the mechanisms of specific substrate and inhibitor recognitions of MAOA and MAOB, we have determined the crystal structure of rat MAOA complexed with the specific inhibitor, clorgyline, at 3.2A resolution [30].

Physical interactions of MAOB


Enzymatic interactions of MAOB

  • Additional studies revealed that MMPP was a poor substrate of only MAO B (Km,app = 9.5 mM) and that acid treatment of MMPP led to the formation of a product that could be readily oxidized by both MAO A and B. Similar acid pretreatment of TMMP yielded a product that was a much poorer substrate for MAO B than the parent compound [33].

Regulatory relationships of MAOB


Other interactions of MAOB

  • Interestingly, ERalpha or ERbeta alone have no effect on MAO-B promoter activity but can down-regulate the activation function of ERRs, whereas glucocorticoid receptor does not [4].
  • The ability of ERRs to stimulate MAO-B promoter activity was reduced in ER-positive MCF-7 and T47D cells [4].
  • The COMT L allele modifies the association between MAOB polymorphism and PD in Taiwanese [38].
  • CONCLUSION: Significant associations with PD were found in polymorphisms of NAT2, MAOB, GSTT1, and tRNAGlu [39].
  • We investigated whether genetic variants of MAO-B intron 13 and DRD2 TaqIB polymorphism could be associated with smoking status among control subjects [40].

Analytical, diagnostic and therapeutic context of MAOB


  1. Detection and analysis of four polymorphic markers at the human monoamine oxidase (MAO) gene in Japanese controls and patients with Parkinson's disease. Nakatome, M., Tun, Z., Shimada, S., Honda, K. Biochem. Biophys. Res. Commun. (1998) [Pubmed]
  2. Increased activities of MAOA and MAOB in autopsied brain tissue from cirrhotic patients with hepatic encephalopathy. Rao, V.L., Giguère, J.F., Layrargues, G.P., Butterworth, R.F. Brain Res. (1993) [Pubmed]
  3. Obesity is associated with genetic variants that alter dopamine availability. Need, A.C., Ahmadi, K.R., Spector, T.D., Goldstein, D.B. Ann. Hum. Genet. (2006) [Pubmed]
  4. Estrogen-related receptors-stimulated monoamine oxidase B promoter activity is down-regulated by estrogen receptors. Zhang, Z., Chen, K., Shih, J.C., Teng, C.T. Mol. Endocrinol. (2006) [Pubmed]
  5. Molecular characterization of monoamine oxidases A and B. Abell, C.W., Kwan, S.W. Prog. Nucleic Acid Res. Mol. Biol. (2001) [Pubmed]
  6. Pathological gambling and DNA polymorphic markers at MAO-A and MAO-B genes. Ibañez, A., de Castro, I.P., Fernandez-Piqueras, J., Blanco, C., Saiz-Ruiz, J. Mol. Psychiatry (2000) [Pubmed]
  7. Association of monoamine oxidase A gene polymorphism with Alzheimer's disease and Lewy body variant. Takehashi, M., Tanaka, S., Masliah, E., Ueda, K. Neurosci. Lett. (2002) [Pubmed]
  8. Monoamine oxidase genes polymorphisms and mood disorder. Muramatsu, T., Matsushita, S., Kanba, S., Higuchi, S., Manki, H., Suzuki, E., Asai, M. Am. J. Med. Genet. (1997) [Pubmed]
  9. Association analysis between mood disorder and monoamine oxidase gene. Lin, S., Jiang, S., Wu, X., Qian, Y., Wang, D., Tang, G., Gu, N. Am. J. Med. Genet. (2000) [Pubmed]
  10. A reversible monoamine oxidase A inhibitor (moclobemide) facilitates smoking cessation and abstinence in heavy, dependent smokers. Berlin, I., Saïd, S., Spreux-Varoquaux, O., Launay, J.M., Olivares, R., Millet, V., Lecrubier, Y., Puech, A.J. Clin. Pharmacol. Ther. (1995) [Pubmed]
  11. Increased stress response and beta-phenylethylamine in MAOB-deficient mice. Grimsby, J., Toth, M., Chen, K., Kumazawa, T., Klaidman, L., Adams, J.D., Karoum, F., Gal, J., Shih, J.C. Nat. Genet. (1997) [Pubmed]
  12. Isolation of a candidate gene for Norrie disease by positional cloning. Berger, W., Meindl, A., van de Pol, T.J., Cremers, F.P., Ropers, H.H., Döerner, C., Monaco, A., Bergen, A.A., Lebo, R., Warburg, M. Nat. Genet. (1992) [Pubmed]
  13. Inhibition of monoamine oxidase B in the brains of smokers. Fowler, J.S., Volkow, N.D., Wang, G.J., Pappas, N., Logan, J., MacGregor, R., Alexoff, D., Shea, C., Schlyer, D., Wolf, A.P., Warner, D., Zezulkova, I., Cilento, R. Nature (1996) [Pubmed]
  14. MPTP toxicity: implications for research in Parkinson's disease. Kopin, I.J., Markey, S.P. Annu. Rev. Neurosci. (1988) [Pubmed]
  15. Association of a monoamine oxidase B allele with Parkinson's disease. Kurth, J.H., Kurth, M.C., Poduslo, S.E., Schwankhaus, J.D. Ann. Neurol. (1993) [Pubmed]
  16. Simultaneous MAO-B and COMT inhibition in L-Dopa-treated patients with Parkinson's disease. Lyytinen, J., Kaakkola, S., Ahtila, S., Tuomainen, P., Teräväinen, H. Mov. Disord. (1997) [Pubmed]
  17. A new formulation of selegiline: improved bioavailability and selectivity for MAO-B inhibition. Clarke, A., Brewer, F., Johnson, E.S., Mallard, N., Hartig, F., Taylor, S., Corn, T.H. Journal of neural transmission (Vienna, Austria : 1996) (2003) [Pubmed]
  18. The therapeutic potential of moclobemide, a reversible selective monoamine oxidase A inhibitor in Parkinson's disease. Sieradzan, K., Channon, S., Ramponi, C., Stern, G.M., Lees, A.J., Youdim, M.B. Journal of clinical psychopharmacology. (1995) [Pubmed]
  19. Safety of selegiline (deprenyl) in the treatment of Parkinson's disease. Heinonen, E.H., Myllylä, V. Drug safety : an international journal of medical toxicology and drug experience. (1998) [Pubmed]
  20. Monoamine oxidase inhibitors. A review of antidepressant effectiveness. Quitkin, F., Rifkin, A., Klein, D.F. Arch. Gen. Psychiatry (1979) [Pubmed]
  21. Human monoamine oxidase A and B genes exhibit identical exon-intron organization. Grimsby, J., Chen, K., Wang, L.J., Lan, N.C., Shih, J.C. Proc. Natl. Acad. Sci. U.S.A. (1991) [Pubmed]
  22. X-linked recessive primary retinal dysplasia is linked to the Norrie disease locus. Ravia, Y., Braier-Goldstein, O., Bat-Miriam, K.M., Erlich, S., Barkai, G., Goldman, B. Hum. Mol. Genet. (1993) [Pubmed]
  23. Characterization of a YAC containing part or all of the Norrie disease locus. Chen, Z.Y., Sims, K.B., Coleman, M., Donnai, D., Monaco, A., Breakefield, X.O., Davies, K.E., Craig, I.W. Hum. Mol. Genet. (1992) [Pubmed]
  24. Molecular cloning of canine monoamine oxidase subtypes A (MAOA) and B (MAOB) cDNAs and their expression in the brain. Hashizume, C., Suzuki, M., Masuda, K., Momozawa, Y., Kikusui, T., Takeuchi, Y., Mori, Y. J. Vet. Med. Sci. (2003) [Pubmed]
  25. Human liver MAO-A and MAO-B separated by immunoaffinity chromatography with MAO-B-specific monoclonal antibody. Denney, R.M., Fritz, R.R., Patel, N.T., Abell, C.W. Science (1982) [Pubmed]
  26. Norrie disease gene is distinct from the monoamine oxidase genes. Sims, K.B., Ozelius, L., Corey, T., Rinehart, W.B., Liberfarb, R., Haines, J., Chen, W.J., Norio, R., Sankila, E., de la Chapelle, A. Am. J. Hum. Genet. (1989) [Pubmed]
  27. Imidazoline/guanidinium binding domains on monoamine oxidases. Relationship to subtypes of imidazoline-binding proteins and tissue-specific interaction of imidazoline ligands with monoamine oxidase B. Raddatz, R., Parini, A., Lanier, S.M. J. Biol. Chem. (1995) [Pubmed]
  28. Dosage-sensitive X-linked locus influences the development of amygdala and orbitofrontal cortex, and fear recognition in humans. Good, C.D., Lawrence, K., Thomas, N.S., Price, C.J., Ashburner, J., Friston, K.J., Frackowiak, R.S., Oreland, L., Skuse, D.H. Brain (2003) [Pubmed]
  29. Structure of the human gene for monoamine oxidase type A. Chen, Z.Y., Hotamisligil, G.S., Huang, J.K., Wen, L., Ezzeddine, D., Aydin-Muderrisoglu, N., Powell, J.F., Huang, R.H., Breakefield, X.O., Craig, I. Nucleic Acids Res. (1991) [Pubmed]
  30. Structure of rat monoamine oxidase A and its specific recognitions for substrates and inhibitors. Ma, J., Yoshimura, M., Yamashita, E., Nakagawa, A., Ito, A., Tsukihara, T. J. Mol. Biol. (2004) [Pubmed]
  31. Dual functions of transcription factors, transforming growth factor-beta-inducible early gene (TIEG)2 and Sp3, are mediated by CACCC element and Sp1 sites of human monoamine oxidase (MAO) B gene. Ou, X.M., Chen, K., Shih, J.C. J. Biol. Chem. (2004) [Pubmed]
  32. Transcription factor binding to the core promoter of the human monoamine oxidase B gene in the cerebral cortex and in blood cells. Ekblom, J., Garpenstrand, H., Damberg, M., Chen, K., Shih, J.C., Oreland, L. Neurosci. Lett. (1998) [Pubmed]
  33. Studies of the in vitro oxidation of 1-methyl-4-(1-methylpyrrol-2-yl)-4-piperidinol and its dehydration product 1,2,3,6-tetrahydro-1-methyl-4-(methylpyrrol-2-yl) pyridine by human monoamine oxidases A and B. Bembenek, M.E. Life Sci. (1990) [Pubmed]
  34. Structural comparison of human monoamine oxidases A and B: mass spectrometry monitoring of cysteine reactivities. Hubalek, F., Pohl, J., Edmondson, D.E. J. Biol. Chem. (2003) [Pubmed]
  35. Regulation of human monoamine oxidase B gene by Sp1 and Sp3. Wong, W.K., Chen, K., Shih, J.C. Mol. Pharmacol. (2001) [Pubmed]
  36. Reduction in glial fibrillary acidic protein mRNA abundance induced by (-)-deprenyl and other monoamine oxidase B inhibitors in C6 glioma cells. Li, X.M., Qi, J., Juorio, A.V., Boulton, A.A. J. Neurochem. (1993) [Pubmed]
  37. Platelet monoamine oxidase B (MAO-B) activity and its relationship to DL-fenfluramine-induced prolactin response in healthy men. Eriksson, M., Berggren, U., Fahlke, C., Engel, J., Balldin, J. Journal of neural transmission (Vienna, Austria : 1996) (2006) [Pubmed]
  38. The COMT L allele modifies the association between MAOB polymorphism and PD in Taiwanese. Wu, R.M., Cheng, C.W., Chen, K.H., Lu, S.L., Shan, D.E., Ho, Y.F., Chern, H.D. Neurology (2001) [Pubmed]
  39. Variability and validity of polymorphism association studies in Parkinson's disease. Tan, E.K., Khajavi, M., Thornby, J.I., Nagamitsu, S., Jankovic, J., Ashizawa, T. Neurology (2000) [Pubmed]
  40. Genotype combinations for monoamine oxidase-B intron 13 polymorphism and dopamine D2 receptor TaqIB polymorphism are associated with ever-smoking status among men. Costa-Mallen, P., Costa, L.G., Checkoway, H. Neurosci. Lett. (2005) [Pubmed]
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