Naunyn-Schmiedeberg's Archives of Pharmacology

, Volume 322, Issue 3, pp 198–202 | Cite as

The deamination of dopamine by human brain monoamine oxidase

Specificity for the two enzyme forms in seven brain regions
  • Anne-Marie O'Carroll
  • Christopher J. Fowler
  • Jack P. Phillips
  • Iqdam Tobbia
  • Keith F. Tipton


The deamination of dopamine has been studied in seven regions of human brain. Both A and B forms of the enzyme were found to be active towards this substrate. The ratio of activities of MAO-A: MAO-B was found to vary considerably from brain region to brain region, from about 1∶1 for the cerebral and cerebellar cortex to about 1∶2 for the pons and medula oblongata. Enzyme titration studies and comparisons of the substrate specificities of MAO-A and MAO-B across the brain indicated that dopamine was metabolised by the same MAO active centres as other monoamines. In the cerebral cortex, the Km values of MAO-A and-B towards dopamine were found to be 210 and 230 μM, respectively, indicating that the relative contributions of these two forms towards the oxidation of this substrate will not be significantly affected by changes in its concentration.

Key words

Human brain Dopamine Monoamine oxidase Clorgyline Deprenyl 


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Copyright information

© Springer-Verlag 1983

Authors and Affiliations

  • Anne-Marie O'Carroll
    • 1
  • Christopher J. Fowler
    • 1
  • Jack P. Phillips
    • 2
  • Iqdam Tobbia
    • 2
  • Keith F. Tipton
    • 1
  1. 1.Biochemistry DepartmentTrinity CollegeDublin 2Ireland
  2. 2.St. Laurence's HospitalDublin 7Ireland

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