Pentigetide is a sythsis pepetide (Asp-Ser-Asp-Pro-Arg or D-S-D-P-R), also know as “HEPP” for “Human IgE Pentapeptide”. Pentigetide can not produce IgE inhibition in several different systems, due to the aspartic acids in HEPP changed into an asparagine.
References:
[1]. Hamburger R N. Recent Studies with Human IgE Pentapeptide (HEPP)[M]//New Trends in Allergy. Springer, Berlin, Heidelberg, 1981: 311-319.