Soybean Leaves Contain Multiple Lipoxygenases

Chromatofocusing of soybean (Glycine max L.) leaf lipoxygenases revealed three distinct peaks of activity. Based on their isoelectric points (pls), pH optima, and mutant analysis it appears that the leaf isozymes are different from those described from mature soybean seed. At least one leaf lipoxygenase appears to differ from those found in hypocotyls. The pls of the main bands of the three leaf lipoxygenase peaks are 6.67, 5.91, and 5.67. The pH optima curves of three active fractions exhibit peaks at pH 6.2, 5.5, and 8.5, respectively. One of the fractions has two polypeptides with slightly different molecular weights, both of which react to soybean seed lipoxygenase antibodies. The other two fractions contain a polypeptide of unit molecular weight reacting with the lipoxygenase antibodies.