Abstract
This study aimed to clarify the relationship between amyloplast size (age) and activities of alkaline pyrophosphatase (PPase) and branching enzyme (BE) within developing Zea mays L. endosperm cells. PPase and BE activities per starch granule were increased when the organelle grew in size, although decreased when calculated per granule surface area. The amyloplast specific PPase and the stromal marker enzyme BE had identical distribution (percent of total activity) in the stroma. The amount of free Pi increased in the stroma with the increased granule size up to 8 μ in diameter (about one third of the final size) and then remained steady. The maximum Pi content at this granule size was 5.2 mmol per 106 amyloplasts (about 5.5 fmol per granule) and PPase activity released about 1 nmol min-1 per 106 amyloplasts. Attempts to detect endogenous PPi in amyloplasts were unsuccessful.
Original language | English |
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Pages (from-to) | 41-46 |
Number of pages | 6 |
Journal | Journal of Plant Physiology |
Volume | 146 |
Issue number | 1-2 |
DOIs | |
State | Published - 1995 |
Keywords
- ADH
- alcohol dehydrogenase
- Amyloplasts
- BE
- branching enzyme
- branching enzyme
- DAP
- days after pollination
- fresh weight
- FW
- maize
- PPase
- pyrophosphatase
- pyrophosphatase
- starch
- sup
- supernatant