10 or 20 µl of freshly prepared total protein from Arabidopsis thaliana suspension culture (A), 10 or 20 µl of total protein (older extract) from Arabidopsis thaliana suspension culture (B), 10 or 20 µl of total leaf extract from Nicotiana tabacum (C), 10 or 20 µl of freshly prepared total protein from Nicotiana tabacum leaf protoplasts (D), 10 or 20 µl total protein from older extract of Nicotiana tabacum leaf protoplasts (E) , extracted with buffer containing 100 mM Tris (pH 7.8), 200 mM NaCl, 1 mM EDTA, 2% (v/v) beta-mercaptoethanol and 0.2% (v/v) Triton X-100, were separated on 8% SDS-PAGE and blotted 2h to nitrocellulose (semidry blot at 200 mA and RT). Blots were blocked with 5% (w/v) milk powder and 1% (w/v) BSA over night at 4°C with agitation. Blot was incubated in the primary antibody at a dilution of 1:2 000 for 1h at RT with agitation. The antibody solution was decanted and the blot was rinsed briefly twice, then washed once for 15 min and 3 times for 5 min in TBS-T at RT with agitation. Blot was incubated in secondary antibody (anti-rabbit IgG HRP conjugated) diluted to 1:10 000 in blocking solution for 45 min. at RT with agitation. The blot was washed as above and developed for 5 min with ECL according to the manufacturers instructions. Exposure time was 120 seconds.