ADK activity in leaves from Col-0 and adk1−/adk1− mutant plants
Arabidopsis leaves from 3-week-old plants were sampled after 12 h in dark, and chloroplasts were isolated as described by Tauberger et al. (2000). ADK activity was measured in both the plastidial fraction and the supernatant with and without Triton (0.01%) following the protocol described by Kleczkowski and Randall (1986). Values are expressed in nmol min−1 mg protein−1 ± se and are means from three replicates. Numbers in bold type denote significant differences determined by the Student's t test (P < 0.05) from Col-0.