In vitro biosynthesis and chemical characterization of beta-lipotropin, gamma-lipotropin, and beta-endorphin in rat pars intermedia.
Three 3-hr incubations of pars intermedia cells from 40 rat pituitaries with [35S]methionine, [3H]lysine, and [3H]leucine sufficed for the identification and chemical characterization of biosynthesized beta-lipotropin, gamma-lipotropin, and beta-endorphin. From the molecular weight, migration on polyacrylamide gels, and sequence Met5, Lys9, Leu14,17, rat beta-endorphin was shown to be identical to its sheep homologue and no trace of Leu5 beta-endorphin could be detected. Rat beta-lipotropin differs from that of sheep in its elution properties on CM-cellulose, and its sequence shows Leu2,10,14, Lys20. Rat gamma-lipotropin shows the same NH2-terminal sequence as beta-lipotropin and is again different from its sheep homologue. The identification of rat beta-lipotropin was confirmed by its selective cleavage into beta-endorphin after trypsin digestion of the citraconylated peptide, a property not observed with rat gamma-lipotropin.
D000595:Amino Acid Sequence; D000818:Animals; D004723:Endorphins / Q000096:biosynthesis* / Q000302:isolation & purification; D066298:In Vitro Techniques; D008297:Male; D008970:Molecular Weight; D010903:Pituitary Gland, Anterior / Q000378:metabolism*; D051381:Rats; D008083:beta-Lipotropin / Q000096:biosynthesis* / Q000302:isolation & purification
D004723:Endorphins; D008083:beta-Lipotropin