Characterization of slow reacting substances (SRSs) of rat basophilic leukemia (RBL-1) cells: effect of cysteine on SRS profile.
When RBL-1 cells were incubated with L-cysteine (7.5 mM) and the ionophore A23187, the slow reacting substances SRS-GSH and SRS-Cys-Gly were formed. When L-cysteine was omitted in the incubation, SRS-GSH and SRS-Cys were isolated but only a trace amount of SRS-Cys-Gly was detectable. Each of the characterized SRSs was accompanied by an as yet uncharacterized structural isomer showing UV absorption at 278 nm. L-Cysteine and other thiols inhibited an aminopeptidase that transforms the highly bioactive SRS of anaphylaxis (SRS-Cys-Gly) into the less bioactive SRS-Cys. SRS-GSH, SRS-Cys-Gly, and SRS-Cys may be readily distinguished from each other by means of their bioactivities, antagonism by FPL 55712, and relative susceptibilities to the actions of soybean lipoxygenase, microsome-bound leucine aminopeptidase, and gamma-glutamyl transpeptidase.
D000595:Amino Acid Sequence; D000818:Animals; D012898:Autacoids / Q000097:blood* / Q000378:metabolism; D002478:Cells, Cultured; D003545:Cysteine / Q000494:pharmacology*; D005978:Glutathione / Q000378:metabolism; D007931:Leucyl Aminopeptidase / Q000037:antagonists & inhibitors; D007942:Leukemia, Experimental / Q000032:analysis; D007951:Leukemia, Myeloid / Q000032:analysis*; D051381:Rats; D005723:gamma-Glutamyltransferase / Q000378:metabolism
D012898:Autacoids; D005723:gamma-Glutamyltransferase; D007931:Leucyl Aminopeptidase; D005978:Glutathione; D003545:Cysteine