Table I. Comparison of galactolipid synthesis activity and chloroplast envelope contamination of various fractions isolated from Arabidopsis cells deprived for Pi for 12 h.
|
|
E37
|
OEP21
|
Incorporated galactose
|
|
|---|---|---|---|---|
| Relative units | Relative units | nmol.mg−1.h−1 | Relative units | |
| Chloroplasts | 100 | 100 | 25.9 | 100 |
| Cells | 9.6 | 9.5 | 1.8 | 6.9 |
| Crude mitochondria | 67.2 | 64.5 | 16.6 | 64.1 |
| Purified mitochondria | 13.4 | 14.4 | 2.8 | 10.8 |
Mitochondria fractions were prepared at different stages of purification as described in Materials and methods. Proteins were analyzed by SDS-PAGE and Western blot, and chloroplast envelope contamination was defined by comparing anti-E37 or OEP21 ECL signal intensity of 10, 5, and 2.5 μg protein of a unique chloroplast fraction and 20, 10, and 5 μg of each mitochondria fraction.