Table I.
Activities of marker enzymes in the vacuolar preparations of barley mesophyll protoplasts
Marker enzyme activities for mitochondria (NAD-malic dehydrogenase), chloroplasts (NADP-gyceraldehydphosphate dehydrogenase, Glc-phosphate isomerase), ER (NADPH-cytochrome-c-reductase), and cytosol (Glc-phosphate isomerase, NAD-malic dehydrogenase) were measured in protoplast and vacuolar fractions. The percentage of contamination was calculated assuming an exclusive localization of α-Mannosidase in the vacuole (Martinoia et al., 1981).
| Marker Enzyme | Activities per 106 Protoplasts | Activities per 106 Vacuoles | % in Vacuole Preparations |
|---|---|---|---|
| nkat | nkat | ||
| α-Mannosidase | 0.15 | 0.147 | 98 |
| NADP-gyceraldehydphosphate dehydrogenase (chloroplast) | 5.7 | 0.009 | 0.16 |
| Glc-phosphate isomerase (cytosol, chloroplast) | 0.35 | 0.003 | 0.96 |
| NAD-malic dehydrogenase (mitochondria, chloroplast, cytosol) | 12.8 | 0.069 | 0.54 |
| NADPH-cytochrome-c-reductase (ER) | 0.32 | 0.27 | 8.4 |