Biochemical aspects of the visual process IV. Aldehydes and cation permeability of artificial phospholipid micelles

Abstract

1. 1. Addition of retinaldehyde to phosphatidylethanolamine liposomes increased the leakage rate of 86Rb +. At low concentrations retinol and retinoic acid did not show this effect, while the ion leakage from phosphatidylcholine liposomes was not influenced by any of these vitamin A compounds. 2. 2. Similar results were obtained with the series benzaldehyde, benzylalcohol and benzoic acid; only the combination of benzaldehyde and phosphatidylethanolamine caused an increase in ion leakage. 3. 3. Fluorodinitrobenzene caused a increase in ion leakage from liposomes only if phosphatidylethanolamine was present. 4. 4. The interaction between retinaldehyde and phosphatidylethanolamine was shown to consist of Schiff base formation. 5. 5. The relevance of these findings for the visual process is discussed.