vip , the vip analogs [ d-his1 ] vip , [ d-ser2 ] vip , [ d-asp3 ] vip and [ d-ala4 ] vip , phi , [ d-phe4 ] phi , and secretin inhibited the binding of both ligands in a concentration range of 10 ( -11 ) m to 10 ( -5 ) m and with a selectivity factor varying from 18,000 to 0.1 .
C1416526
ser2
C1517880
binding