Effects of beta-carotene on soybean lipoxygenase activity: kinetic studies


Serpen A., Gokmen V.

EUROPEAN FOOD RESEARCH AND TECHNOLOGY, vol.224, no.6, pp.743-748, 2007 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 224 Issue: 6
  • Publication Date: 2007
  • Doi Number: 10.1007/s00217-006-0368-z
  • Journal Name: EUROPEAN FOOD RESEARCH AND TECHNOLOGY
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.743-748
  • Keywords: lipoxygenase, noncompetitive inhibition, beta-carotene, inhibition mechanism, inhibition kinetic, RADICALS RELATIONSHIP, PARTIAL-PURIFICATION, LINOLEATE OXIDATION, ACID, INHIBITION, ENZYME, 15-LIPOXYGENASE-1, COOXIDATION, PLANT
  • Hacettepe University Affiliated: Yes

Abstract

beta-carotene directly influences the amount of soybean lipoxygenase (LOX) in the reaction medium available for the catalytic conversion of linoleic acid into corresponding hydroperoxides. Inhibition of LOX by beta-carotene was predominantly of the noncompetitive type. The mean K (m(app)) value was estimated to be 13.25 mu M +/- 0.15 mu M for linoleic acid while the mean K (i) value was estimated to be 2.56 mu M +/- 0.14 mu M for beta-carotene. V (m(app)) values decreased from 1.90 Delta A (234 nm)/min to 0.38 Delta A (234 nm)/min as the concentration of beta-carotene increased. The IC50 value for beta-carotene was 2.49 mu M +/- 0.21 mu M. It is shown here that beta-carotene is an efficient LOX inhibitor, effective at low-level concentration enzyme-dependent peroxidation of linoleic acid. Presence of beta-carotene keeps LOX in its reduced form of Fe(II) and the oxidation of linoleic acid is prevented.