Design a benzotriazole linker for on-resin C-terminal modification of a peptide and analogues for biomedical application

• Main Author: ANAND SELVARAJ
• Other Authors: Chai-Lin Kao
• Format: Others
• Language: en_US
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/fp5vje

博士 === 高雄醫學大學 === 醫藥暨應用化學系博士班 === 106 === SPPS methodology has brought about a revolution in peptide and protein chemistry and thousands of peptides have now been synthesized using this approach. It has created new possibilities in the research fields of peptide-protein chemistry and nucleic acid chemistry as well as other field. It has greatly stimulated progress in biochemistry, molecular biology, pharmacology, medicine and material science. It is also of great practical importance, both for the development of new drugs and for gene technology. The SPPS approach is more convenient method to prepare the peptide on solid support through the stepwise synthesis. However, the strict spacing between each of the branches which might lead to aggregation of the peptides on the resin and also purification remains a challenge. In my PhD thesis, we have explored the Bt-resin based ORL approaches for peptide and derivatives synthesis through SPPS, which proved to be effective and enabled to synthesis the peptide derivatives for further specific applications. The first part of my PhD work (shown in chapter 2) mainly focuses to address the C-terminal functionalization of peptides on resins, a convenient and efficient method was developed and used to transform resin-bound 3,4-diaminobenzoic acid species with isoamyl nitrite to resin-bound benzotriazole (Bt) linkers that served as leaving groups displaced by nucleophiles during cleavage of the peptide-resin connection. This newly developed resin was found to be suitable for typical Fmoc chemistry and no epimerization of amino acid residues was observed. The cleavage step allowed for the use of various nucleophiles. The chemoselective condensation between Bt-resin and nucleophile requires no reagent. This approach proceeds to serve as a novel on-resin chemoselective ligation for the synthesis of peptide and peptide derivatives. The second part of my PhD work (shown chapter 3) mainly focuses to establishing a novel on-resin ligation (ORL) for synthesis of peptide and derivatives because ORL has advantages of convenient synthesis and easy purification procedures. We first prepare the elastin peptide through the ORL approach. 20-Mer peptide were successfully achieved using solid supports with a good yield. We then constructed a different length and generation peptide dendrimers with lysine dendron core. We also applied this method to synthesis the hydrophobic rich bivalent peptide dendrimer (29 residues) with good yield. We also strived to synthesis the head to tail cyclic peptide, sunflower trypsin inhibitor by the ORL ligation. This approach was efficiently applied to prepare the different length cyclic peptide. The third part of my PhD program aims to apply ORL approach to prepare the peptide decorated with different generation of PAMAM dendrimers. In this study, we developed an enzyme responsive peptide decorated dendrimer based nanomaterial as a potential drug delivery vehicle for cancer chemotherapy. For this purpose, we used peptide as a targeting agent to decorated to surface of the G2 PAMAM dendrimer as a drug carrier. This dendrimer was able to encapsulate the anticancer drug and dye in the interior of the core. It constitutes a novel targeting peptide and multivalent to improve the water solubility and selectivity of the drug. In summary, my PhD program mainly contributes to develop a new resin for solid phase peptide synthesis. Results from these studies have allowed us to advance SPPS and will further help us to improve our ability with a view to constructing versatile peptide derivatives and broaden their applications in the arenas of biomedical sciences.