Lipoxygenase Activity Test

Method description

Samples are homogenized and enzymes are extracted into a cold, pH 6.5 buffer.  A protein determination by the Method of Bradford is performed on the enzyme extract (supernatant) to normalize subsequent enzyme results to the efficiency of the protein extraction.  The enzyme extract is mixed with linoleic acid or arachidonic acid.  Lipoxygenase activity is measured spectrophotometrically by the rate of formation of the fatty acid hydroperoxide at 234nm.

Acceptable matrices

cereal grains, doughs, pastas, and vegetables

Equipment

UV/Vis spectrophotometer, homogenizer, microplate reader

Method reference

Axelrod B, Cheesbrough TM, and Laakso S (1981) Lipoxygenase from soybeans, In “Methods in Enzymology”, Vol. 71. (Ed.) JM Lowenstein.  Academic Press, New York

Ben-Aziz A, Grossman S, Ascarelli I, and Budowski P (1970) Linoleate oxidation induced by lipoxygenase and heme proteins: a direct spectrophotometric assay.  Anal. Biochem. 34:8

Reportable unit

units per gram.
One unit is defined as the change in absorbance at 234nm per minute from the hydroperoxidation of the cis, cis-1,4 pentadiene containing fatty acid.
One unit is equivalent to the oxidation of 0.12 micromoles of linoleic acid.

Sample size requirements

20 grams

Information required by submitter

Estimates of activity if available.
Composition of sample matrix.

Additional information

Please keep and ship samples frozen if possible.