Turkelson C M, Solomon T E, Bussjaeger L, Turkelson J, Ronk M, Shively J E, Ho F J, Reeve J R
Veterans Administration Medical Center, Kansas City, MO 64128.
Peptides. 1988 Nov-Dec;9(6):1255-60. doi: 10.1016/0196-9781(88)90189-1.
Cholecystokinin-58 (CCK-58) was purified from rat intestines using an extraction method that yields large amounts of this peptide. Greater than 30% of total CCK immunoreactivity eluted before CCK-39 upon gel permeation chromatography (Sephadex G-50) if extracts were loaded onto Sep Pak cartridges before freezing. If the extracts were frozen and stored at -70 degrees C for six weeks, only 20% of the material eluted in this region and total immunoreactivity was reduced by 50%, suggesting that proteases were active under these storage conditions. This early eluting peak was purified by reverse phase and ion-exchange HPLC to a single absorbance peak. Microsequence analysis of this peak detected AVLRPDSEP which is the amino terminus of rat CCK-58 predicted from the rat preprocholecystokinin cDNA. Because degradation of CCK-58 occurred in these extracts, it is possible that CCK-58 is the predominant molecule form in the rat small intestine.
