Slow reacting substances (SRSs): the structure identification of SRSs from rat basophil leukaemia (RBL-1) cells.

Slow Reacting Substances have been produced from RBL-l cells by calcium ionophore A23187 and purified to homogeneity by high pressure liquid chromatography (HPLC). The structure of the major biologically active species has been determined by mass spectrometric examination of the intact molecule as a derivative, together with amino-acid analysis and sequence determination. The characteristic triene chromophore which we originally identified in immunologically generated SRS-A is present in RBL-l SRS, and we determine the structure of this SRS as the thio-substituted dipeptide, 5-hydroxy-6-cysteinylglycinyl-7,9,11,14-eicosatetraenoic acid.