Effect of hemoglobin concentration on the oxidation of linoleic acid.

The inhibitory effect of high concentrations of hemoglobin on the oxidation of linoleic acid was related to the ability of hemoglobin to associate with the fatty acid. Ultracentrifugation of the mixture of hemoglobin and potassium linoleate revealed that approximately 880 moles of linoleic acid could associate with 1 mole of hemoglobin. High concentrations of hemoglobin apparently reduced the amount of free linoleic acid accessible to the heme group, thus preventing the oxidation of the fatty acid. With low hemoglobin concentrations, at which the oxidation began immediately after the addition of the catalyst, the amount of free linoleic acid was considerably greater than that of bound linoleic acid.