Comparison of the disulfide bond arrangements of human recombinant and bovine brain heparin binding neurite-promoting factors.

Heparin binding neurite-promoting factor (HBNF) is a highly basic 136 amino acid protein containing 10 cysteine residues. We have determined the redox status and the disulfide arrangement of the cysteine residues in HBNF from bovine brain and refolded human recombinant protein produced in E. coli. Our data indicate that all 10 cysteines are involved in disulfide bond formation. The disulfide linkages of human recombinant and bovine brain HBNF, as determined after proteolytic digestions of the non-reduced proteins by peptide mapping and sequence analysis are: Cys15-Cys44, Cys23-Cys53, Cys30-Cys57, Cys67-Cys99 and Cys77-Cys109. Thus, recombinant HBNF has the same disulfide arrangement as the native brain-derived protein.