Synthesis and Some Biological Properties of 1-Deamino-4-Glu-Oxytocin (1-β-Mercaptopropionic Acid–4-Glutamic Acid–Oxytocin) and its Use in Preparing a Hormone–Agarose Complex

Abstract

1-Deamino-4-Glu-oxytocin (1-β-mercaptopropionic acid – 4-glutamic acid – oxytocin) was synthesized by sequential reduction by sodium in liquid ammonia and oxidation by hydrogen peroxide of the octapeptide derivative, S-benzyl-β-mercaptopropionyl-tyrosyl-isoleucyl-γ-O-benzyl-glutamyl-asparaginyl-S-benzyl-cysteinyl-prolyl-leucyl-glycinamide. The oxidation analogue was isolated and purified by partition chromatography in two different solvent systems followed by exclusion chromatography on Sephadex G-25. It was found to possess approximately 13 I.U. of uterotonic activity, 34 I.U. of milk ejection activity, and 83 I.U. of milk ejection-like activity per milligram, measured on an isolated strip of lactating mouse mammary gland. 1-Deamino-4-Glu-oxytocin was coupled to AH-Sepharose 4B by way of the free γ-carboxyl group of its residue of glutamic acid. The water soluble 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride caused the coupling with approximately 70% effectiveness. The resultant peptide–agarose complex had low biological potency in the assay of milk ejection-like activity.