A major part of platelet-derived growth factor purified from human platelets is a heterodimer of one A and one B chain.
Platelet-derived growth factor, PDGF, purified from human platelets is a disulfide-bonded dimer consisting of two homologous polypeptide chains denoted A and B; it has not been known whether it is a heterodimer or a mixture of homodimers. We present here evidence that a major part of PDGF has a heterodimer structure. A highly homogeneous, 31-kDa PDGF was purified in the presence of protease inhibitors and shown to contain both chains by means of immunoprecipitations with peptide antisera specific for the A and B chains, respectively. The susceptibility of PDGF to mild acid treatment and its chromatographic behavior in reversed-phase high performance liquid chromatography and immobilized metal ion affinity chromatography, as compared to A and B chain homodimers, is consistent with a heterodimer structure. Analysis of PDGF purified according to our routine, large scale procedure revealed the major part to have a heterodimer structure. In addition, B chain homodimers were also found. With the demonstration that a major part of PDGF purified from human platelets occurs as a heterodimer, all three dimeric forms of PDGF have been identified. The following nomenclature to distinguish the various forms is suggested: PDGF-AA, a homodimer of A chains; PDGF-AB, a heterodimer; PDGF-BB, a homodimer of B chains; PDGF, any dimeric form of A or B chains.
Hammacher
A
A
Ludwig Institute for Cancer Research, Uppsala, Sweden.
Hellman
U
U
Johnsson
A
A
Ostman
A
A
Gunnarsson
K
K
Westermark
B
B
Wasteson
A
A
Heldin
C H
CH
D000936:Antigen-Antibody Complex / Q000032:analysis; D001792:Blood Platelets / Q000032:analysis*; D000939:Epitopes / Q000032:analysis; D006801:Humans; D007106:Immune Sera; D046911:Macromolecular Substances; D008970:Molecular Weight; D010982:Platelet-Derived Growth Factor / Q000276:immunology / Q000302:isolation & purification*
D000936:Antigen-Antibody Complex; D000939:Epitopes; D007106:Immune Sera; D046911:Macromolecular Substances; D010982:Platelet-Derived Growth Factor