Cycloviolacin O2 is a cyclic peptide that has three disulphide bonds and reported for various biological activities. I am looking for the sources where I can get the chemically synthesized peptides with all disulphide bonds.
There are a number of peptide synthesis companies operating. The only way of knowing if they'll produce your peptide is to enquire to them directly. Many have online quotation tools, which include disulfide bond specification. I can recommend Proteogenix as being quite good for synthesis generally.