Aqueous solid-phase peptide synthesis (ASPPS): A novel concept of peptide synthesis

• Main Author: Knauer, Sascha
• Format: Others
• Language: en
• Published: 2020
• Online Access: https://tuprints.ulb.tu-darmstadt.de/9066/1/Dissertation%20Sascha%20Knauer%20Aqueous%20solid-phase%20peptide%20synthesis%20%28ASPPS%29.pdf; Knauer, Sascha <http://tuprints.ulb.tu-darmstadt.de/view/person/Knauer=3ASascha=3A=3A.html> (2020): Aqueous solid-phase peptide synthesis (ASPPS): A novel concept of peptide synthesis.Darmstadt, Technische Universität, DOI: 10.25534/tuprints-00009066 <https://doi.org/10.25534/tuprints-00009066>, [Ph.D. Thesis]

In the frame of the present work, an efficient and sustainable aqueous solid-phase peptide synthesis was developed based on a novel sulfonated derivative of fluorenyl protecting group. The viability of this approach and its application range was demonstrated upon the assembly of 22 biologically active peptides. To make access to aqueous peptide synthesis, coupling efficency was assessed in water-based systems applying respective Nα-Smoc amino acids and using different activation approaches. In our hands, several water-compatible activating additives were found appropriate, with EDC-Cl, Oxima and HOPO being the most efficient ones. Our experiments showed that although coupling of amino acids in water gave reasonable yields and purity of peptides, the addition of organic co-solvents enhanced coupling performance significantly. Additional studies on enantiomeric composition showed no increased racemization levels during the ASPPS process. Ionic properties of the Smoc protecting group gave rise to an elegant approach allowing for a reliable purification of synthetic peptides. To that end, all the by-products originating from incomplete couplings are labelled with charged sulfo-tags and can be easily removed by a post-assembly ion-exchange chromatography. Our studies showed that sulfo-tad capping could also be applied to other methods of peptide on-support production. This method allows tailoring of purification strategy depending on required purity grade and could be used to refine the wastewater.