Native hGLP-2(1-33) binds to the hGLP2-R with highest affinity
among the tested ligands
In order to determine whether agonists and antagonists competed
similarly, we measured heterologous binding (figure 3) by displacing the
two radioligands with the four unlabeled peptides; hGLP-2(1-33),
hGLP-2(3-33), hGLP-2(1-33,M10Y) and hGLP-2(3-33,M10Y). Overall, all four
ligands were able to compete with both radioligands, with no significant
differences in their binding affinities whether using the agonist or the
antagonist radioligand (figure 3a and table 2). However, native
hGLP-2(1-33) had a 4- to 5-fold higher affinity compared to the other
three hGLP-2 variants (figure 3 and table 2). The decreased affinity of
hGLP-2(1-33,M10Y) compared to hGLP-2(1-33) is consistent with the
slightly decreased potency for hGLP-2(1-33,M10Y) compared to
hGLP-2(1-33) (figure 1b).