Evidence for the location of the receptor-binding site of human erythropoietin at the carboxyl-terminal domain.
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.
Fibi
M R
MR
Behringwerke AG, Marburg, Germany.
Stüber
W
W
Hintz-Obertreis
P
P
Lüben
G
G
Krumwieh
D
D
Siebold
B
B
Zettlmeissl
G
G
Küpper
H A
HA
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D001330:Electronic Data Processing; D004586:Electrophoresis / Q000379:methods; D000939:Epitopes / Q000235:genetics; D004921:Erythropoietin / Q000378:metabolism; D006801:Humans; D007106:Immune Sera / Q000276:immunology; D015151:Immunoblotting; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000032:analysis / Q000276:immunology / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000276:immunology / Q000378:metabolism / Q000648:ultrastructure*; D017467:Receptors, Erythropoietin; D011994:Recombinant Proteins / Q000276:immunology / Q000378:metabolism
D000596:Amino Acids; D000939:Epitopes; D007106:Immune Sera; D010446:Peptide Fragments; D011956:Receptors, Cell Surface; D017467:Receptors, Erythropoietin; D011994:Recombinant Proteins; D004921:Erythropoietin