Characterization of canine intestinal cholecystokinin-58 lacking its carboxyl-terminal nonapeptide. Evidence for similar post-translational processing in brain and gut.
An antibody raised against a synthetic cholecystokinin (CCK) analog, (1-27)-(CCK)-33, corresponding to the midregion of CCK-58, detected immunoreactivity in intestinal extracts which eluted between the positions of CCK-33/39 and CCK-58 on high performance liquid chromatography. This peak, lacking carboxyl-terminal cholecystokinin immunoreactivity, was purified by reverse phase and cation-exchange chromatographies. Amino acid, mass spectral, and microsequence analysis established that it was the amino-terminal desnonapeptide fragment of cholecystokinin-58, (1-49)-CCK-58. It was demonstrated further that CCK-58 has less biological activity than CCK-8, suggesting that the amino terminus either sterically hindered the ability of CCK-58 to exert its biological activity or that its amino terminus acted at another site to inhibit release of amylase from rat pancreatic acini. The desnonapeptide of CCK-58 by itself had no biological activity, nor did it affect CCK-8-stimulated amylase release from isolated rat pancreatic acini, suggesting that the amino terminus shields the carboxyl terminus from expressing its biological activity. Its presence in intestine suggests that it is released into the circulation where it could be detected by midregion antibodies. The presence of high proportions of (1-49)-CCK-58 indicates that most CCK-8 is directly derived from CCK-58. Its occurrence in brain and intestine indicates similar processing for procholecystokinin in both tissues.
Reeve
J R
JR
Center for Ulcer Research and Education, Veterans Administration Hospital at Wadsworth, Los Angeles, California 90073.
Eysselein
V
V
Eberlein
G A
GA
Chew
P
P
Ho
F J
FJ
Huebner
V D
VD
Shively
J E
JE
Lee
T D
TD
Liddle
R A
RA
D000595:Amino Acid Sequence; D000681:Amylases / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000378:metabolism; D002766:Cholecystokinin / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism; D004285:Dogs; D066298:In Vitro Techniques; D007413:Intestinal Mucosa / Q000378:metabolism; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000302:isolation & purification; D011499:Protein Processing, Post-Translational; D051381:Rats; D012636:Secretory Rate; D013329:Structure-Activity Relationship
D010446:Peptide Fragments; C038823:cholecystokinin 58; D002766:Cholecystokinin; D000681:Amylases