Breadcrumb

 
 

Purification and kinetics of phenylpropanoid O-methyltransferase activities from Brassica oleracea

Title:

Purification and kinetics of phenylpropanoid O-methyltransferase activities from Brassica oleracea

De Carolis, Emidio and Ibrahim, Ragai K. (1989) Purification and kinetics of phenylpropanoid O-methyltransferase activities from Brassica oleracea. Biochemistry and Cell Biology, 67 (11-12). pp. 763-769. ISSN 0829-8211

[img]
Preview
PDF - Published Version
1002Kb

Official URL: http://dx.doi.org/10.1139/o89-115

Abstract

Two phenylpropanoid O-methyltransferase isoforms were purified to homogeneity from young cabbage leaves. They catalyzed the meta-O-methylation of caffeic and 5-hydroxyferulic acids to ferulic and sinapic acids, respectively. Both isoforms I and II exhibited different elution patterns from a Mono Q column, distinct apparent pIs on chromatofocusing, different product ratios, and stability on adenosine–agarose affinity column. On the other hand, both isoforms had similar apparent molecular masses (42 kilodaltons) and a pH optimum of 7.6. They exhibited no requirement for divalent cations and were both irreversibly inhibited by iodoacetate. Substrate interaction kinetics of the more stable isoform I, using the 5-hydroxyferulic acid and S-adenosyl-L-methionine, gave converging lines. Product inhibition studies showed competitive inhibition between S-adenosyl-L-methionine and S-adenosyl-L-homocysteine and non-competitive inhibition between the phenylpropanoid substrate and its methylated product. The kinetic patterns are consistent with an ordered bi bi mechanism, where S-adenosyl-L-methionine is the first substrate to bind and S-adenosyl-L-homocysteine is the last product released.

Divisions:Concordia University > Faculty of Arts and Science > Biology
Item Type:Article
Refereed:Yes
Authors:De Carolis, Emidio and Ibrahim, Ragai K.
Journal or Publication:Biochemistry and Cell Biology
Date:1989
Funders:
  • Natural Sciences and Engineering Research Council of Canada
  • Department of Higher Education, Government of Quebec
Keywords:phenylpropanoid O-methyltransferase, purification, isoforms, adenosine–agarose affinity chromatography, kinectic mechanism
ID Code:6776
Deposited By:DANIELLE DENNIE
Deposited On:13 Jul 2010 11:32
Last Modified:08 Dec 2010 18:07
All items in Spectrum are protected by copyright, with all rights reserved. The use of items is governed by Spectrum's terms of access.

Repository Staff Only: item control page

Document Downloads

More statistics for this item...

Concordia University - Footer