Use of the phenomenon of annihilation delayed fluorescence for investigating the structural organization of the sarcoplasmic reticulum

The method of recording annhilation delayed fluorescence in the membranes of the sarcoplasmic reticulum and in the liposomes of dimyristoyl phosphatidylcholine at 30 °C has been used to study the interaction of the triplet probes between themselves and with the quencher (ferrocene). As triplet probes the authors used: perilene, 7,12-dimethyl benzanthracene and 4-(2-anthryl)-butanoic acid. The mean decay time of the annhilation delayed fluorescence of perilene and 4-(2-anthryl)-butanoic acid in the sarcoplasmic reticulum was respectively 4·2 × 10^-5 and 2·3 × 10^-5 sec. The rate constants of quenching of the triplet state of perilene by ferrocene are equal to 2·1 × 10⁷ (mm/g lipid)^-1sec^-1 in the sarcoplasmic reticulum and 4·5 × 10⁷ (mm/g lipid)^-1sec^-1 in the liposomes. Analysis of the results indicates that the sarcoplasmic reticulum lipids in the liquid crystalline state form continuous extended portions containing over 7 × 10³ lipid molecules free of serious obstacles to the diffusion of the probes.