1. Multi-cystine peptides
The synthesis of peptides containing multiple disulfide bonds can be challenging. This is due to the fact that multiple disulfide bonds can form randomly within any peptides that contain enough cysteines. Few companies around the world offer multi-cysteine peptide synthesis services for containing two disulphide bonds and none of them can synthesize peptides with more. GenScript, however, has developed two separate ways around this obstacle, making peptide synthesis containing multiple disulphide bonds both possible and affordable.
The first of these is stepwise oxidation utilizing different protecting groups to protect each cysteine pair during the Fmoc SPPS synthesis process. Different deprotecting conditions are used to deprotect each protecting group. These are carefully selected based on the specific needs of the client's project. With subsequent stepwise oxidizations of the disulphide bonds during the liquid phase, we can accurately synthesize peptides with more than two disulfide bonds with great accuracy.
The second method works through folding and oxidization. The key point is to take the peptide at its folding condition in liquid phase and oxidize all the cysteines to form a peptide containing native multiple disulfide bonds in one step and then employ zymohydrolysis to orient the position of disulfide bonds.
Case study: Peptide A
Sequence: H - Cys - Asn - Cys - ... ... ... - Cys - ... ... ... - Cys - ... ... ... - NH2
Disulfide bridge: 1 - 11, 3 - 15
HPLC results:
MS results:
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