Photoinduced charge separation in liposomes containing chlorophyll a. I. Photoreduction of copper(II) by potassium ascorbate through liposome bilayer containing purified chlorophyll a.
Biochimica et biophysica acta
confidence
Key findings
Photoinduced charge separation study: photoreduction of Cu(II) by potassium ascorbate through liposome bilayer with chlorophyll a; no clinical/biological endpoints.
View source on PubMed (PMID 223634) ↗
- Sample size
- Not reported
- Population
- In vitro phosphatidylcholine bilayer liposomes containing purified chlorophyll a
- Dosing
- Not reported
- Duration
- Not reported
- Route
- In vitro
- Blinding
- not_reported
- Controls
- none
- Drug class
- porphyrin pigment
Full abstract
Photosensitivity of dispersion of phosphatidylcholine bilayer liposomes containing purified chlorophyll alpha was examined. The reduction of Cu(II) in the solution outside liposomes was observed upon illumination with visible light under anaerobic condition by means of ESR. The rate of photoreduction was significantly increased by a reductant, potassium ascorbate, localized in the solution of the opposite side of the membrane. The aciton spectrum of the reduction agreed with the absorption spectrum of chlorphyll a in the dispersion. The amount of bleach chlorophyll a was negligible compared with that of reduced (Cu(II). These facts lead to the conclusion that the potoinduced redox reactions at both the membrane-solution interfaces are coupled with each other through the bilayer of each liposome. Kinetic analysis of the reactions based on a possible reaction scheme was carried out and some of the kinetic parameters were determined.