Biochemical Characterization, Kinetic Analysis and Molecular Modeling of Recombinant Vegetative Lipoxygenases from Soybean

Abstract

Plants in general have multiple lipoxygenase isoforms that exhibit distinct biochemical attributes and discrete cellular and sub-cellular localization patterns. This suggests that plant lipoxygenases are multifunctional and contribute to several physiological processes during growth and development. Soybeans have at least eight isoforms. Three that are localized to the seed (L-1; L-2; L-3) have been characterized extensively. The vegetative organs have five additional isoforms that are not well characterized. To better understand the potential cellular function of these vegetative lipoxygenases (VLXs), kinetic parameters and pH profiles with multiple substrates coupled with structural studies reveal differences within this family of enzymes. In addition, clear differences exist between VLX-A,-B &-E and VLX-C &-D in the exposed loops of the-barrel, O 2 cavity and entry site of the subcavity IIa. Therefore, based on distinct patterns of activity and structure, the existence of functional subgroups among the five VLX isoforms was confirmed.