Interaction of N-(phosphonomethyl)glycine with some respiratory chain enzymes of isolated corn-shoot mitochondria.

Spectrophotometric measurements of the activities of some dehydrogenases and electron transfer complexes of isolated corn-shoot mitochondria revealed that N-(phosphonomethyl)glycine (PMG), a broad-spectrum, non-selective, and post-emergence herbicide, at a concentration of 6.25 x 10(-4)M enhanced by about 10% the activities of NAD+-linked malate and NAD+-linked isocitrate dehydrogenases. At concentrations of 5 x 10(-3)M and 10 x 10(-3)M PMG, the activities of succinate and the NAD+-linked dehydrogenases were reduced by at least 10% and 25%, respectively. Although no effect was observed on the activities of the electron transfer complexes at lower concentrations of PMG, these enzymes were inhibited by at least 10% and 20%, respectively, at 5.0 x 10(-3)M and 10 x 10(-3)M PMG.