CHARACTERIZATION OF DISULFIDE LINKAGES IN PLATELET-DERIVED GROWTH-FACTOR AA

Intermolecular and intramolecular disulfide linkages of recombinant hu man platelet-derived growth factor A chain dimer were determined by ch emical methods including selective reduction-alkylation, peptide isola tion, or detection of diphenylthiohydantoin derivative of cystine from Edman reactions. Cys-37 and Cys-46 were selectively reduced with redu cing agents under native conditions and revealed to be involved in int ermolecular bridges. Other disulfide linkages including Cys-10-Cys-54, Cys-43-Cys-91, and Cys-47-Cys-93 form intramolecular bridges. The dis ulfide structure is homologous to that of platelet-derived growth fact or B chain dimer. (C) 1994 Academic Press, Inc.