Methodology for the synthesis of peptide C-terminal aldehydes has been investigated. Modification of a linker system, based on a terabenzosuberyl construct, has been demonstrated to be suitable for the synthesis of peptide C-terminal semicarbazones. The route has been fully optimised to yield a series of peptide C-terminal semicarbazones and the corresponding peptide aldehydes. The chemical synthesis of deglycosylated human interferon-gamma (143 residues) has been carried out. The purification of this protein has been investigated and a short purification protocol developed which is sufficiently general to allow application to other similar protein systems. Purification and characterisation of the synthetic interferon-gamma molecule has been completed and folding of the molecule attempted.