Cholecystokinin octapeptide purified from brains of Australian marsupials.

Abstract

Cholecystokinin octapeptides (CCK8s) have been purified from methanol extracts of two brains from each of two Australian marsupials, Tammar Wallaby and Eastern Quoll, containing 3 nmol and 2 nmol of the peptides, respectively. Immunoreactive CCK was concentrated on QMA SepPak cartridges and purified by two successive HPLC steps on Nova C18 radial-pak cartridges. The sequence of each of the peptides is identical with that previously reported for Old World mammals (DYMGWMDF). This is in contrast to the previously reported sequence for CCK8 from the South American hystricomorphs, guinea pig and chinchilla, which differs in a substitution of valine for methionine in position 3 from the NH2-termi..