Taxonomic distribution of plant glutathione S-transferases acting on xenobiotics.

Soluble and microsomal glutathione S-transferase activities for five model xenobiotics (nitrobenzene derivatives), two pesticidal xenobiotics (atrazine and fluorodifen), and a natural substrate (cinnamic acid), were determined in 59 different plant species and four plant cell suspension cultures. These enzyme activities were widely distributed over the plant kingdom with certain species showing particularly high activities. Marine macroalgae had a remarkably broad substrate range that included the substrates atrazine and fluorodifen. It is concluded that the evolutionary 'green liver' concept derived for xenobiotic metabolism in higher plant species is also valid for the constitutive soluble and microsomal glutathione S-transferases of lower plant species.