title: Isolation and characterization of sulphated and nonsulphated forms of cholecystokinin-58 and their action on gallbladder contraction.
abstract: Cholecystokinin (CCK) exists in multiple molecular forms with different polypeptide lengths and the absence or presence of sulphation. We have isolated sulphated and nonsulphated forms of CCK-58 from porcine intestine and have determined their bioactivities in a guinea-pig gallbladder contraction assay. Both forms co-eluted in cation-exchange chromatography and in several rounds of reverse-phase (RP)-HPLC, but separated upon RP-HPLC using a water/acetonitrile system with heptafluorobutyric acid as counter ion. Nonsulphated CCK-58 was the form detected by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry because of desulphation in that process. The biological activity of CCK-58 and CCK-33 is equipotent, although the kinetics of the response differ. Sulphated CCK-58 was found to be 35 times more potent than nonsulphated CCK-58. In contrast, sulphated CCK-8 is 150 times more potent than nonsulphated CCK-8, and for sulphated and nonsulphated CCK-33, the activities differ by a factor of 100. This type of correlation indicates that the N-terminal end of CCK-58 partially compensates for the decrease in activity arising from the lack of sulphated tyrosine. Given its fairly high bioactivity, nonsulphated CCK-58 may have a physiological significance.
authors.affiliation: Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.
authors.forename: V
authors.initials: V
authors.lastname: Bonetto
authors.forename: H
authors.initials: H
authors.lastname: Jörnvall
authors.forename: M
authors.initials: M
authors.lastname: Andersson
authors.forename: S
authors.initials: S
authors.lastname: Renlund
authors.forename: V
authors.initials: V
authors.lastname: Mutt
authors.forename: R
authors.initials: R
authors.lastname: Sillard
mesh_terms: D000818:Animals; D002766:Cholecystokinin / Q000737:chemistry* / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid; D019075:Electrophoresis, Capillary; D005704:Gallbladder / Q000187:drug effects*; D006168:Guinea Pigs; D007422:Intestines / Q000737:chemistry; D009119:Muscle Contraction; D010446:Peptide Fragments / Q000737:chemistry / Q000494:pharmacology; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013431:Sulfates / Q000737:chemistry* / Q000494:pharmacology; D013552:Swine
chemical_list: D010446:Peptide Fragments; D013431:Sulfates; C038823:cholecystokinin 58; D002766:Cholecystokinin