Inhibitory effect of sucrose on the plasma membrane H+ pump activity and possible involvement of the C-terminal region in the sucrose effect

The effect of sucrose on the plant plasma membrane H+ pump activity is uncl ear. In the plasma membrane vesicles from rye leaves high concentrations of sucrose had significant inhibitory effects on the plasma membrane H+ pump activity. Fusicoccin and trypsin treatment experiments suggest that the C-t erminal region of the H+ pump may partially but significantly be involved i n the sucrose effect.