Abstract
The activity and presence of isoforms of NADP-malic enzyme (EC 1.1.1.40, NADP-ME) were studied in non-transgenic and transgenic Nicotiana benthamiana plants containing potyviral gene for helper component protease (HC-pro) and in plants infected by Potato virus Y strain NTN (PVYNTN). No significant changes in enzyme activities and isoenzyme pattern were observed due to foreign gene introduction and PVYNTN infection.
However, the activity and isoenzyme composition of NADP-ME measured in extracts from different parts of the plants showed significant differences. Non-denaturating electrophoresis followed by specific detection of NADP-ME activity in polyacrylamide gel detected the presence of only one isoform in roots and younger leaves.
Two isoforms of NADP-ME were detected in older leaves and stem (MW ~248 000 and ~280 000) and three isoforms correspond to tetramer, dimer and monomer were found in flowers.