| Abstract: | Mammalian vasoactive intestinal peptide (VIP) has been reported to be identical in four species. This report describes the extraction of guinea pig (GP) intestinal VIP, its purification and sequence. Frozen intestines were extracted in five volumes of methanol and the methanol cakes reextracted with acid. VIP in the acid extract was concentrated onto ion-exchange cellulose and was brought to final purity through a series of HPLC steps. GP VIP differs from other mammalian VIP's by four amino acid substitutions: (sequence in text) This is further evidence that the GP gastroenteropancreatic axis has a unique evolutionary separation from other mammals. |
