Crucial role of position 40 for interactions of CCK-58 revealed by sequence of cat CCK-58.
Evidence suggests that amino terminal extensions of CCK-8 affect the carboxyl terminal bioactive region of CCK. Cat CCK-58 was purified by low pressure reverse phase and ion-exchange chromatography steps and several reverse phase HPLC steps. The purified peptide and its tryptic fragments were characterized by mass spectral analysis and microsequence analysis. The structure of cat CCK-58 is: AVQKVDGEPRAHLGALLARYIQQARKAPSGRMSVIKNLQSLDPSHRISDRDY(SO3) MGWMDF-amide. Cat and dog CCK-58 are identical except for position 40 which is serine in cat and asparagine in dog. Radioimmunoassay detected cat CCK-58 about 1/10th as well as dog CCK-58, indicating a marked effect on C-terminal immunoreactivity. Cat CCK-58 with a serine at position 40, the same residue found in pig, mouse, cow and rabbit CCK-58, can be used as a unique bioprobe for defining how amino terminal amino acids influence the structure and bioactivity of the carboxyl terminal region of CCK.
Reeve
Joseph R
JR
CURE: Digestive Diseases Research Center, Veterans Administration Greater Los Angeles Healthcare System, Los Angeles, CA 90073, USA.
Rosenquist
Grace L
GL
Keire
David A
DA
Chew
Peter
P
Nicholas
Hugh B
HB
Davis
Michael T
MT
Lee
Terry D
TD
Shively
John E
JE
Backus
Robert C
RC
D000595:Amino Acid Sequence; D000818:Animals; D002415:Cats; D002766:Cholecystokinin / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D004285:Dogs; D008297:Male; D008969:Molecular Sequence Data; D025941:Protein Interaction Mapping; D017434:Protein Structure, Tertiary / Q000502:physiology; D020539:Sequence Analysis, Protein; D012694:Serine / Q000378:metabolism
D012694:Serine; C038823:cholecystokinin 58; D002766:Cholecystokinin