Synthesis and biological evaluation of N alpha-hydroxysulfonyl-[Nle28,31]-CCK26-33

Two analogues of [Nle28,31]-CCK26-33 containing an N-terminal acetyl or N-terminal hydroxysulfonyl moiety were prepared and characterized. Both analogues were equipotent to native CCK26-33 in four bioassays, demonstrating that N-terminal sulfation of CCK26-33 analogues is compatible with full biological activity.