Plants containing lipoxygenase

The tomato plant contains a number of enzymes that we have already discussed and that may be important mediators of resistance to insects (e.g., polyphenol oxidases, peroxidases, lipoxygenases, ureases, chitinases, phenylalanine and tyrosine ammonia lyases, en-dopolygalacturonases). We discuss here the potential interaction of these enzymes. 

Lipoxygenases (LOXs) represent a group of polyunsaturated fatty acid oxidases that are apparently ublqultlous In eukaryotic organisms. There are a growing number of reports of the presence of this enzyme In various human and other animal tissues. The list of plants containing active LOXs also continues to expand. 

Lipoxygenases, which catalyse the oxidation of unsaturated fatty acids containing the cis,cis-l,4-pentadiene moiety to the corresponding 1 -hydroperoxy-f rans,ds-2,4-diene (Table 2.3), are widely distributed in plants and animals. The mammalian... 

Galliard and Phillips 144) have found that homogenates of potato tubers contain an enzyme which converts the primary lipoxygenase product of linoleic acid, the 9-D-hydroperoxyoctadecadienoic acid, into an 18-carbon ether (Figure 3). Here too, cleavage of the Gig chain must occur. The formation and role of possible cleavage products from linoleic and linolenic acids in aroma and physiology of plant tissues have already been mentioned. 

Lipoxygenase is iron that contains dioxygenase and is found in plants and mammals, also produced by some microorganisms. It has been established that the lipoxygenase from soybeans can catalyse the oxidation of a wide range of endogenous chemicals (KuUcami 1996). 

Lipoxygenases (LOX) constitute a family of lipid peroxidizing enzymes, which are distributed widely in the plant and animal kingdoms. These enzymes preferentially metabolize substrates that are polyunsaturated fatty acids containing a series of cis double bonds, which are the essential fatty acids for human beings (Kuhn Thiele, 1999). Lipoxygenases are dioxygenases in nature and... 

Table 11.4 Plant tissues containing high levels of lipoxygenase activity (from Galliard and Chan, 1980, with permission)...

Plant Tissues Containing High Levels of Lipoxygenase Activity"... 

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