ISOLATION OF α-MELANOTROPIN AND N, O-DIACETYLSERINE1-α-MELANOTROPIN FROM PORCINE PITUITARY EXTRACTS

Abstract
In the course of isolation of α-melanotropin (α-MSH) from porcine pituitary extracts, a peptide with identical amino acid composition but slightly less polar properties compared to α-MSH was detected and isolated by partition chromatography. The new peptide was identified as N, O-diacetyl-Ser1 -α-MSH by high resolution nuclear magnetic resonance spectroscopy. N, O-diacetyl-Ser1 -α-MSH was readily converted to α-MSH by incubation at pH 9.5. The O-acetyl analog of α-MSH was found to be as active as α-MSH in stimulating lipolysis in isolated rabbit adipocytes.