Spring cabbage peroxidases--potential tool in biocatalysis and bioelectrocatalysis

Phytochemistry. 2008 Feb;69(3):627-36. doi: 10.1016/j.phytochem.2007.08.018. Epub 2007 Sep 29.

Abstract

Two fractions of peroxidase activity, cationic Px-cat and anionic Px-ani, were isolated and partially purified (143.5- and 5.49-fold, respectively) from homogenate of spring cabbage heads. Optimum pH for both fractions is 6.0; however, Px-cat is almost equally active at neutral pH (7.0) while Px-ani reveals high activity in more acidic pHs (with 60% of maximum activity at pH 3.0). Optimal temperature for both fractions was 40 degrees C. Px-ani possessed much higher thermal stability at 40-50 degrees C (60% of remaining activity after 144h of incubation) than Px-cat. The peroxidases remained fully active during 4 weeks of storage at 4 degrees C. Kinetic studies revealed that Px-cat and Px-ani had lower apparent Km values for ABTS (0.0377 and 0.0625mM) and o-dianisidine (0.357 and 0.286mM) than for guaiacol (6.41 and 13.89mM). The best substrate for Px-cat was pyrogallol and for Px-ani-o-dianisidine. Px-cat immobilized on polyanionic PyBA-modified carbon electrode was found to produce linear repetitive signals upon consecutive additions of hydrogen peroxide during at least 1-week period and to work effectively under buffered and non-buffered conditions. These properties were comparable with those of commercially available horseradish peroxidase. Stability of the hybrid bioelectrocatalytic film and low costs of extraction and partial purification of Px-cat make it a highly promising enzyme for practical applications, including construction of bioelectrodes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites
  • Brassica / enzymology*
  • Catalysis
  • Electrochemistry
  • Enzyme Activation
  • Hydrogen Peroxide / chemistry
  • Hydrogen-Ion Concentration
  • Kinetics
  • Pectins / chemistry
  • Peroxidases / chemistry*
  • Peroxidases / isolation & purification*
  • Substrate Specificity
  • Temperature

Substances

  • Pectins
  • Hydrogen Peroxide
  • Peroxidases
  • polygalacturonic acid