Biology:Dopamine beta-hydroxylase

From HandWiki
Revision as of 12:27, 12 February 2024 by AIposter (talk | contribs) (url)
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Short description: Mammalian protein found in Homo sapiens


A representation of the 3D structure of the protein myoglobin showing turquoise α-helices.
Generic protein structure example
dopamine beta-monooxygenase
Identifiers
EC number1.14.17.1
CAS number9013-38-1
Databases
IntEnzIntEnz view
BRENDABRENDA entry
ExPASyNiceZyme view
KEGGKEGG entry
MetaCycmetabolic pathway
PRIAMprofile
PDB structuresRCSB PDB PDBe PDBsum
Gene OntologyAmiGO / QuickGO

Dopamine beta-hydroxylase (DBH), also known as dopamine beta-monooxygenase, is an enzyme (EC 1.14.17.1) that in humans is encoded by the DBH gene. Dopamine beta-hydroxylase catalyzes the conversion of dopamine to norepinephrine.

Dopamine is converted to norepinephrine by the enzyme dopamine β-hydroxylase; ascorbic acid serves as a cofactor

The three substrates of the enzyme are dopamine, vitamin C (ascorbate), and O2. The products are norepinephrine, dehydroascorbate, and H2O.

DBH is a 290 kDa copper-containing oxygenase consisting of four identical subunits, and its activity requires ascorbate as a cofactor.[1]

It is the only enzyme involved in the synthesis of small-molecule neurotransmitters that is membrane-bound, making norepinephrine the only known transmitter synthesized inside vesicles. It is expressed in noradrenergic neurons of the central nervous system (i.e. locus coeruleus) and peripheral nervous systems (i.e. sympathetic ganglia), as well as in chromaffin cells of the adrenal medulla.

Mechanism of catalysis

Based on the observations of what happens when there is no substrate, or oxygen, the following steps seem to constitute the hydroxylation reaction.[2][3]

In the absence of oxygen, dopamine or other substrates, the enzyme and ascorbate mixture produces reduced enzyme and dehydroascorbate. Exposing the reduced enzyme to oxygen and dopamine results in oxidation of the enzyme and formation of noradrenaline and water, and this step doesn't require ascorbate.

Although details of DBH mechanism are yet to be confirmed, DBH is homologous to another enzyme, peptidylglycine α-hydroxylating monooxygenase (PHM). Because DBH and PHM share similar structures, it is possible to model DBH mechanism based on what is known about PHM mechanism.[4]

Substrate specificity

{{Annotated image 4 | caption = {{{caption|In humans, catecholamines and phenethylaminergic trace amines are derived from the amino acid {{nowrap|L-phenylalanine}}.}}} | header_background = #F0F8FF | header = Biosynthetic pathways for catecholamines and trace amines in the human brain<ref name="Trace amine template 1">Broadley KJ (March 2010). "The vascular effects of trace amines and amphetamines". Pharmacol. Ther. 125 (3): 363–375. doi:10.1016/j.pharmthera.2009.11.005. PMID 19948186. </ref>[5][6] | alt = Graphic of catecholamine and trace amine biosynthesis | image = Catecholamine and trace amine biosynthesis.png | image-width = 580 | image-left = 5 | image-top = 0 | align = left | width = 590 | height = 585 | annot-font-size = 14 | annot-text-align = center | annotations =

{{annotation|50|565|{{if pagename|Adrenaline=Adrenaline|Epinephrine=Epinephrine|Catecholamine=Epinephrine|other=Epinephrine}}}}

{{annotation|245|60|{{if pagename|Phenethylamine=Phenethylamine|Trace amine=Phenethylamine|Neurobiological effects of physical exercise={{highlight|Phenethylamine}}|other=Phenethylamine}}}}

{{annotation|245|565|{{if pagename|Norepinephrine=Norepinephrine|Adrenaline=Noradrenaline|Catecholamine=Norepinephrine|other=Norepinephrine}}}}

{{annotation|440|295|p-Octopamine}}}}

primary
pathway
brain
CYP2D6
minor
pathway
DBH
DBH

Dopamine beta-hydroxylase catalyzes the hydroxylation of not only dopamine but also other phenylethylamine derivatives when available. The minimum requirement seems to be the phenylethylamine skeleton: a benzene ring with a two-carbon side chain that terminates in an amino group.[2]

Assays for DBH activity in human serum and cerebrospinal fluid

DBH activity in human serum could be estimated by a spectrophotometric method [7] or with the aid of Ultra high performance liquid chromatography with Photo Diode Array detector (UHPLC-PDA).[8] A sensitive assay for the detection of DBH activity in cerebrospinal fluid using High-performance liquid chromatography with Electrochemical detector(HPLC-ECD) was also described earlier.[9]

Expression quantitative trait loci (eQTLs) at DBH loci

Genetic variants such as single-nucleotide polymorphisms(SNPs)[10][11] at DBH loci were found to be associated with DBH activity and are well known expression quantitative trait loci. Allele variants at two regulatory SNPs namely rs1611115 [12] and rs1989787 [13] were shown to affect transcription of this gene. Mutations identified in dopamine beta hydroxylase deficiency[14] and non-synonymous SNPs such as rs6271 in this gene were found to cause defective secretion of the protein from the endoplasmic reticulum.[15]

Clinical significance

DBH primarily contributes to catecholamine and trace amine biosynthesis. It also participates in the metabolism of xenobiotics related to these substances; for example, the human DBH enzyme catalyzes the beta-hydroxylation of amphetamine and para-hydroxyamphetamine, producing norephedrine and para-hydroxynorephedrine respectively.[16][17][18]

DBH has been implicated as correlating factor in conditions associated with decision making and addictive drugs, e.g., alcoholism[19] and smoking,[20] attention deficit hyperactivity disorder,[21] schizophrenia,[22] and Alzheimer's disease.[23] Inadequate DBH is called dopamine beta hydroxylase deficiency.

The proximal promoter SNPs rs1989787 and rs1611115 were found to be associated with cognition in schizophrenia subjects.[24] Further these SNPs (rs1989787;rs1611115) and a distal promoter variant 19bp Ins/Del(rs141116007) were associated with scores of Abnormal Involuntary Movement Scale in tardive dyskinesia positive schizophrenia subjects.[24] Of the three variants, the proximal promoter SNP(rs1611115) was associated with Positive and Negative Syndrome Scale(PANSS) scores in tardive dyskinesia positive schizophrenia subjects.[24] The main effect of a putative splice variant in Dopamine beta-hydroxylase namely rs1108580 was found to be associated with Working memory Processing speed in a north Indian Schizophrenia case control study where the G/G genotype of that single-nucleotide polymorphism(SNP) was found to have lower cognitive scores than those with A/A and A/G genotypes. Furthermore the same SNP was associated with Emotion accuracy in healthy controls.[25]

Structure

Experimental DBH structural model based upon in silico prediction and physiochemical validation[26]

It was difficult to obtain a stable crystal of dopamine beta-hydroxylase. Hence an homology model based on the primary sequence and comparison to PHM is available.[26]

However, a crystal structure was also put forward in 2016.[27]

Regulation and inhibition

This protein may use the morpheein model of allosteric regulation.[28]

Inhibitors

Types of dopamine beta-hydroxylase inhibition[clarification needed][citation needed]
HYD[lower-alpha 1] HP[lower-alpha 2] QCA[lower-alpha 3] IQCA[lower-alpha 4] BI[lower-alpha 5] IAA[lower-alpha 6][1]
Competitive Ascorbate Ascorbate Ascorbate Ascorbate Ascorbate Ascorbate
Uncompetitive Tyramine Tyramine
Mixed Tyramine Tyramine Tyramine Tyramine
Ascorbate is cofactor; tyramine is substitute for dopamine, DBH's namesake substrate
  1. ↑ hydralazine
  2. ↑ 2-hydrazinopyridine
  3. ↑ 2-quinoline-carboxylic acid
  4. ↑ l-isoquinolinecarboxylic acid
  5. ↑ 2,2'-biimidazole
  6. ↑ imidazole-4-acetic acid

DBH is inhibited by disulfiram,[29] tropolone,[30] and, most selectively, by nepicastat.[31]

DBH is reversibly inhibited by l-2H-Phthalazine hydrazone (hydralazine; HYD), 2-1H-pyridinone hydrazone (2-hydrazinopyridine; HP), 2-quinoline-carboxylic acid (QCA), l-isoquinolinecarboxylic acid (IQCA), 2,2'-bi-lH-imidazole (2,2'-biimidazole; BI), and IH-imidazole-4-acetic acid (imidazole-4-acetic acid;[2] IAA). HYD, QCA, and IAA are allosteric competitive.[32]

Nomenclature

The systematic name of this enzyme class is 3,4-dihydroxyphenethylamine, ascorbate:oxygen oxidoreductase (beta-hydroxylating).

Other names in common use include:

  • dopamine beta-monooxygenase
  • dopamine beta-hydroxylase
  • membrane-associated dopamine beta-monooxygenase (MDBH)
  • soluble dopamine beta-monooxygenase (SDBH)
  • dopamine-B-hydroxylase
  • 3,4-dihydroxyphenethylamine beta-oxidase
  • 4-(2-aminoethyl) pyrocatechol beta-oxidase
  • dopa beta-hydroxylase
  • dopamine beta-oxidase
  • dopamine hydroxylase
  • phenylamine beta-hydroxylase
  • (3,4-dihydroxyphenethylamine) beta-mono-oxygenase

References

  1. ↑ "Dopamine beta-hydroxylase in health and disease". Critical Reviews in Clinical Laboratory Sciences 12 (3): 241–77. 1980. doi:10.3109/10408368009108731. PMID 6998654. 
  2. ↑ 2.0 2.1 "The Mechanism of Action of Dopamine β-Hydroxylase". Oxidation of Organic Compounds. Advances in Chemistry. 77. 1968. pp. 172–176. doi:10.1021/ba-1968-0077.ch073. ISBN 0-8412-0078-5. 
  3. ↑ "An electron paramagnetic resonance study of 3,4-dihydroxyphenylethylamine beta-hydroxylase". The Journal of Biological Chemistry 241 (10): 2256–9. May 1966. doi:10.1016/S0021-9258(18)96614-7. PMID 4287853. 
  4. ↑ "New insights into copper monooxygenases and peptide amidation: structure, mechanism and function". Cellular and Molecular Life Sciences 57 (8–9): 1236–59. August 2000. doi:10.1007/pl00000763. PMID 11028916. 
  5. ↑ "A renaissance in trace amines inspired by a novel GPCR family". Trends Pharmacol. Sci. 26 (5): 274–281. May 2005. doi:10.1016/j.tips.2005.03.007. PMID 15860375. 
  6. ↑ "The endogenous substrates of brain CYP2D". Eur. J. Pharmacol. 724: 211–218. February 2014. doi:10.1016/j.ejphar.2013.12.025. PMID 24374199. 
  7. ↑ "Photometric Assay of Dopamine-β-Hydroxylase Activity in Human Blood". Clinical Chemistry 18 (9): 980–983. 1972. doi:10.1093/clinchem/18.9.980. PMID 5052101. 
  8. ↑ "Determination of Dopamine-β-hydroxylase Activity in Human Serum Using UHPLC-PDA Detection". Neurochemical Research 43 (12): 2324–2332. 2018. doi:10.1007/s11064-018-2653-1. PMID 30357655. 
  9. ↑ "Highly sensitive assay for dopamine-beta-hydroxylase activity in human cerebrospinal fluid by high performance liquid chromatography-electrochemical detection: properties of the enzyme". Journal of Neurochemistry 37 (2): 289–296. 1981. doi:10.1111/j.1471-4159.1981.tb00454.x. PMID 7264660. 
  10. ↑ "A quantitative-trait analysis of human plasma-dopamine beta-hydroxylase activity: evidence for a major functional polymorphism at the DBH locus". American Journal of Human Genetics 68 (2): 515–22. 2001. doi:10.1086/318198. PMID 11170900. 
  11. ↑ "Deep sequencing identifies novel regulatory variants in the distal promoter region of the dopamine-beta-hydroxylase gene". Pharmacogenetics and Genomics 26 (7): 311–23. 2016. doi:10.1097/FPC.0000000000000214. PMID 26959714. 
  12. ↑ "Human dopamine beta-hydroxylase (DBH) regulatory polymorphism that influences enzymatic activity, autonomic function, and blood pressure". Journal of Hypertension 28 (1): 76–86. 2010. doi:10.1097/HJH.0b013e328332bc87. PMID 20009769. 
  13. ↑ "Human dopamine beta-hydroxylase promoter variant alters transcription in chromaffin cells, enzyme secretion, and blood pressure". American Journal of Hypertension 24 (1): 24–32. 2011. doi:10.1038/ajh.2010.186. PMID 20814407. 
  14. ↑ "Norepinephrine deficiency is caused by combined abnormal mRNA processing and defective protein trafficking of dopamine beta-hydroxylase". Journal of Biological Chemistry 286 (11): 9196–204. 2011. doi:10.1074/jbc.M110.192351. PMID 21209083. 
  15. ↑ "Characterization of SNPs in the dopamine-beta-hydroxylase gene providing new insights into its structure-function relationship". Neurogenetics 18 (3): 155–168. 2017. doi:10.1007/s10048-017-0519-3. PMID 28707163. 
  16. ↑ Glennon RA (2013). Foye's principles of medicinal chemistry (7th ed.). Philadelphia, US: Wolters Kluwer Health/Lippincott Williams & Wilkins. pp. 646–648. ISBN 9781609133450. "The phase 1 metabolism of amphetamine analogs is catalyzed by two systems: cytochrome P450 and flavin monooxygenase. ... Amphetamine can also undergo aromatic hydroxylation to p-hydroxyamphetamine.  ... Subsequent oxidation at the benzylic position by DA β-hydroxylase affords p-hydroxynorephedrine. Alternatively, direct oxidation of amphetamine by DA β-hydroxylase can afford norephedrine." 
  17. ↑ Taylor KB (January 1974). "Dopamine-beta-hydroxylase. Stereochemical course of the reaction". J. Biol. Chem. 249 (2): 454–458. doi:10.1016/S0021-9258(19)43051-2. PMID 4809526. http://www.jbc.org/content/249/2/454.full.pdf. Retrieved 6 November 2014. "Dopamine-β-hydroxylase catalyzed the removal of the pro-R hydrogen atom and the production of 1-norephedrine, (2S,1R)-2-amino-1-hydroxyl-1-phenylpropane, from d-amphetamine.". 
  18. ↑ "Human serum dopamine-β-hydroxylase. Relationship to hypertension and sympathetic activity". Circ. Res. 32 (5): 594–599. May 1973. doi:10.1161/01.RES.32.5.594. PMID 4713201. "Subjects with exceptionally low levels of serum dopamine-β-hydroxylase activity showed normal cardiovascular function and normal β-hydroxylation of an administered synthetic substrate, hydroxyamphetamine.". 
  19. ↑ "Functional polymorphism of the dopamine β-hydroxylase gene is associated with increased risk of disulfiram-induced adverse effects in alcohol-dependent patients". Journal of Clinical Psychopharmacology 32 (4): 578–80. August 2012. doi:10.1097/jcp.0b013e31825ddbe6. PMID 22760354. 
  20. ↑ "Association between dopamine beta hydroxylase rs5320 polymorphism and smoking behaviour in elderly Japanese". Journal of Human Genetics 57 (6): 385–90. June 2012. doi:10.1038/jhg.2012.40. PMID 22513716. 
  21. ↑ "Analysis of polymorphisms in the dopamine beta hydroxylase gene: association with attention deficit hyperactivity disorder in Indian children". Indian Pediatrics 42 (2): 123–9. February 2005. PMID 15767706. 
  22. ↑ "Linkage analysis of plasma dopamine β-hydroxylase activity in families of patients with schizophrenia". Human Genetics 130 (5): 635–43. November 2011. doi:10.1007/s00439-011-0989-6. PMID 21509519. 
  23. ↑ "The dopamine β-hydroxylase -1021C/T polymorphism is associated with the risk of Alzheimer's disease in the Epistasis Project". BMC Medical Genetics 11 (161): 162. 2010. doi:10.1186/1471-2350-11-162. PMID 21070631. 
  24. ↑ 24.0 24.1 24.2 "Association of regulatory variants of dopamine β-hydroxylase with cognition and tardive dyskinesia in schizophrenia subjects". Journal of Psychopharmacology 34 (3): 358–369. 2020. doi:10.1177/0269881119895539. PMID 31913053. 
  25. ↑ "Effect of rs1108580 of DBH and rs1006737 of CACNA1C on Cognition and Tardive Dyskinesia in a North Indian Schizophrenia Cohort". Molecular Neurobiology 60 (12): 6826–6839. 2023. doi:10.1007/s12035-023-03496-4. PMID 37493923. 
  26. ↑ 26.0 26.1 "Structural insight of dopamine β-hydroxylase, a drug target for complex traits, and functional significance of exonic single nucleotide polymorphisms". PLOS ONE 6 (10): e26509. 2011. doi:10.1371/journal.pone.0026509. PMID 22028891. Bibcode: 2011PLoSO...626509K. 
  27. ↑ "The crystal structure of human dopamine β-hydroxylase at 2.9 Å resolution". Science Advances 2 (4): e1500980. 2016. doi:10.1126/sciadv.1500980. PMID 27152332. Bibcode: 2016SciA....2E0980V. 
  28. ↑ "Dynamic dissociating homo-oligomers and the control of protein function". Archives of Biochemistry and Biophysics 519 (2): 131–43. March 2012. doi:10.1016/j.abb.2011.11.020. PMID 22182754. 
  29. ↑ "Inhibition of dopamine- β -hydroxylase by disulfiram". Life Sciences 3 (7): 763–7. July 1964. doi:10.1016/0024-3205(64)90031-1. PMID 14203977. 
  30. ↑ "The inhibitionof dopamine-β-hydroxylase by tropolone and other chelating agents". Biochemical Pharmacology 13 (7): 1103–6. July 1964. doi:10.1016/0006-2952(64)90109-1. PMID 14201135. 
  31. ↑ "Catecholamine modulatory effects of nepicastat (RS-25560-197), a novel, potent and selective inhibitor of dopamine-beta-hydroxylase". British Journal of Pharmacology 121 (8): 1803–9. August 1997. doi:10.1038/sj.bjp.0701315. PMID 9283721. 
  32. ↑ "Inhibition of dopamine beta-hydroxylase by bidentate chelating agents". Biochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology 1037 (2): 240–7. February 1990. doi:10.1016/0167-4838(90)90174-E. PMID 2306475. 

Further reading

External links



Retrieved from "https://handwiki.org/wiki/index.php?title=Biology:Dopamine_beta-hydroxylase&oldid=3600297"