Proteases as Catalysts for Peptide Synthesis

Sonia Barberis Fanny Guzman, Andr6s Illanes, and Josep Ldpez-Santi n Faculty of Chemistry, Biochemistry and Pharmacy, UniversidadNacional de San Luis, Chacabuco y Pedernera, San Luis, Argentina. Phone 54-2652-424689, fax 54-2652-422644 e-mail sbarberi unsl.edu.ar 

Bhalla 2005). In this sense, the technologies for peptide production are not competitive with each other in most of the cases. 

The chemical route is often a better technological option than the biotechnological methods of recombinant DNA and biocatalysis for the synthesis of medium size peptides that comprise most of the pharmaceutically relevant molecules. The synthesis of peptides was originally performed in solution. However, since the introduction of solid-phase synthesis by Merrifield (1986), this technology has gained more relevance (Stewart and Young 1984). 

Research and development in SPPS has conducted to two main schemes of protection, which are known as t-Boc/Bzl and Fmoc/tBu strategies (Chan and White 2000). In t-Boc/Bzl, the t-Boc (tert-butoxycarbonyl) group is used for the protection of the Na amino group and a benzyl or cyclohexyl for the side chains of several amino acids. In Fmoc/tBu, the Fmoc (9-fluorenyl methoxycarbonyl) group is used for the protection of the Na amino group and the tert-butyl group for the protection of the side chains of several amino acids (Albericio 2000). 

Solid matrices should meet several requirements particles should be of conventional and uniform size, mechanically robust, easily filterable, chemically inert and chemically stable under the conditions of synthesis and highly accessible to the 

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