Evidence for the location of the receptor-binding site of human
erythropoietin at the carboxyl-terminal domain
MR Fibi, W Stuber, P Hintz-Obertreis, G Luben, D Krumwieh, B Siebold, G Zettlmeissl and HA Kupper
Behringwerke AG, Marburg, Germany.
Five different peptides (P1: 84-95; P2: 152-166; P3: 52-63; P4: 7-23; P5:
110-123) homologous to relatively hydrophilic regions of human
erythropoietin (huEpo) have been synthesized to identify biologically
active domains of the hormone. All peptides were able to induce high titers
of peptide-specific antibodies in rabbits. Antisera from rabbits induced by
recombinant huEpo (rhuEpo) contained a relatively high amount of antibodies
preferentially directed against three peptides (P2, P4, and P5), of which
P4 comprised the amino-terminal region, P2 the carboxyl-terminus, and P5 an
interior region previously described as the receptor-binding site. The same
three peptides were able to induce rhuEpo-specific antibodies, whereas P1
and P3 lacked this activity. Only peptide-P2-induced antisera inhibited the
biologic activity of rhuEpo in a cell proliferation assay, indicating that
the carboxyl-terminal region of the molecule is essentially involved in the
biologic function of rhuEpo.
Volume 77,
Issue 6,
pp. 1203-1210,
03/15/1991
Copyright © 1991 by The American Society of Hematology
