Incorporation of phytol precursors into chlorophylls of tobacco cell cultures.
Planta
confidence
Key findings
Phytol precursors incorporated into chlorophylls a and b; radioactivity found in phytyl chlorophyllide; no clinical/biological endpoints reported.
View source on PubMed (PMID 24253092) ↗
- Sample size
- Not reported
- Population
- Tobacco cell cultures (in vitro)
- Dosing
- [1-(3)H] GGPP, [1-(3)H] GGMP, [U-(14)C] PhPP at 20-60 µM
- Duration
- 24 h incubation
- Route
- In vitro incubation
- Blinding
- not_reported
- Controls
- not_reported
- Drug class
- porphyrin pigment
Full abstract
The incorporation of [1-(3)H] geranylgeranyl diphosphate (GGPP), [1-(3)H] geranylgeranyl monophosphate (GGMP) and [U-(14)C] phytyl diphosphate (PhPP) into chlorophylls a and b in growing tobacco cell cultures was investigated. The substrates were effectively incorporated into chlorophylls a and b, 3.2% of the total activity of applied GGPP or GGMP and 12.4% of the total activity of applied PhPP being found in chlorophylls a and b after 24 h incubation. The radioactivity was found in phytyl chlorophyllide through-out which means effective hydrogenation of the alcohol moiety in the case of GGPP and GGMP. With increasing substrate concentration, the specific radioactivity of chlorophyll increased up to a saturation level which was reached either at 20-40 μM PhPP or at 60 μM GGPP and GGMP. The specific radioactivity of the chlorophyll formed during the 24-h incubation period was the same as that of the applied substrate at saturating substrate concentration. The specific radioactivity of chlorophyll a was higher than that of chlorophyll b only in the case of PhPP.