Continuous spectrophotometric assays for dopamine beta-monooxygenase based on two novel electron donors: N,N-dimethyl-1,4-phenylenediamine and 2-aminoascorbic acid

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dc.contributor Wichita State University. Department of Chemistry en_US
dc.contributor.author Wimalasena, Kandatege en_US
dc.contributor.author Wimalasena, D. Shyamali en_US
dc.date.accessioned 2012-02-06T17:16:59Z
dc.date.available 2012-02-06T17:16:59Z
dc.date.issued 1991-09-02 en_US
dc.identifier 1785690 en_US
dc.identifier 0370535 en_US
dc.identifier.citation Analytical biochemistry. 1991 Sep 2; 197(2): 353-61. en_US
dc.identifier.issn 0003-2697 en_US
dc.identifier.uri http://hdl.handle.net/10057/4375
dc.description Full text of this article is not available in SOAR. en_US
dc.description.abstract Based on the novel chromophoric electron donors, N,N-dimethyl-1,4-phenylenediamine (DMPD) and 2-amino-2-deoxy-L-ascorbic acid (2-aminoascorbic acid), two sensitive, convenient, and continuous spectrophotometric assays for dopamine beta-monooxygenase (EC are described. Both, DMPD and 2-aminoascorbic acid are kinetically and stoichiometrically well-behaved electron donors for dopamine beta-monooxygenase with kinetic parameters comparable to the most efficient physiological electron donor, ascorbic acid. During dopamine beta-monooxygenase turnover, DMPD is converted to its chromophoric cation radical which is stable under the standard assay conditions. The rate of the enzyme-dependent formation of DMPD cation radical under standard assay conditions could easily be followed at 515 nm with high accuracy and reproducibility. Similarly, dopamine beta-monooxygenase-mediated oxidation of 2-aminoascorbic acid results in the formation of the known, stable chromophoric product, 2,2'-nitrilodi-2(2')-deoxy-L-ascorbic acid (red pigment), which has a very strong absorption maximum at 385 nm. Both the above assays are superior to the existing assays in their convenience, reproducibility, and sensitivity for routine kinetic analysis of dopamine beta-monooxygenase and may be adopted as a simple color test for the enzyme. We propose that the above assays could also be adopted to design continuous and sensitive spectrophotometric assays for ascorbate oxidase, peptidyl alpha-amidating monooxygenase, and the chromaffin granule electron transport protein, cytochrome b561, due to their remarkable similarity to dopamine beta-monooxygenase in the chemistry of catalysis with regard to the electron donor. en_US
dc.format.extent 353-61 en_US
dc.language.iso eng en_US
dc.publisher Elsevier en_US
dc.relation.ispartofseries Analytical biochemistry en_US
dc.relation.ispartofseries Anal. Biochem. en_US
dc.source NLM en_US
dc.subject Research Support, Non-U.S. Gov't en_US
dc.subject.lcsh Ascorbic Acid/chemistry en_US
dc.subject.mesh Animals en_US
dc.subject.mesh Ascorbic Acid/analogs & derivatives en_US
dc.subject.mesh Cattle en_US
dc.subject.mesh Chemistry, Clinical en_US
dc.subject.mesh Chromaffin Granules/enzymology en_US
dc.subject.mesh Dopamine beta-Hydroxylase/analysis en_US
dc.subject.mesh Kinetics en_US
dc.subject.mesh Oxidation-Reduction en_US
dc.subject.mesh Phenylenediamines/chemistry en_US
dc.subject.mesh Spectrophotometry/methods en_US
dc.title Continuous spectrophotometric assays for dopamine beta-monooxygenase based on two novel electron donors: N,N-dimethyl-1,4-phenylenediamine and 2-aminoascorbic acid en_US
dc.type Article en_US
dc.coverage.spacial United States en_US
dc.description.version peer reviewed en_US
dc.rights.holder Copyright © 1991, Elsevier en_US

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