Continuous Flow Peptide Synthesis on Aminopolyoxyethylene-Polystyrene Graft Copolymer using Fmoc-Strategy

Abstract

An insoluble graft copolymer consisting of the covalently bound polyoxyethylene to cross-linked polystyrene (HO-POE-PS) was prepared by anionic polymerization of ethylene oxide on the resin. The copolymer was then converted to the corresponding amino-polymer (H 2 N-POE-PS) and the latter was employed as the solid carrier for peptide synthesis. Although HO-POE-PS has successfully been employed as a carrier for peptide synthesis by the standard shaking procedure using /-butoxycarbonyl-amino acids, now we deemed it of interest to test its suitability for the continuous flow synthesis. Thus, the C-terminal octapeptide of the porcine insulin B chain (B23-30) was prepared by this procedure using a photolabile anchoring group and fluoren-9-ylmethoxycarbonyl-amino acids. All the reactions were carried out in a continuous flow manner in a steel column under pressure using a high-performance liquid chromatography (HPLC) system. At the end of the synthesis, a sample of the proiected peptide was cleaved from the support by photolysis. For the cleavage of another sample, an aqueous solution of sodium carbonate w*s employed. The protected peptide was purified on silica gel and Sephadex-LH 20. All the protecting groups of a sample of the octapeptide were removed with piperidine/dimethylformamide and trifluoroacetic acid and the deblocked peptide was purified by ion-exchange chiomatography. The free peptide was shown to be homogeneous by thin-layer chromatography, HPLC, and electrophoresis. The identify af the free octapeptide was confirmed by aminc-acid analysis, 13 C-nuclear magnetic resonance measurement and field-desorption mass spectiometry. The peptide was also shown to be free of racemization. Kontinuierliche Peptidsynthese auf dem Aminopolyoxyethylen-Polystyrol-Träger in einem Durchflußreaktor unter Verwendung der Fmoc-Strategie

Carbon-13 NMR relaxation times of a tripeptide methyl ester and its polymer-bound analogs

“…The spin-lattice relaxation times were determined from the relaxation data by using a regression analysis that was incorporated in the 7\ routine of the Bruker acquisition and processing program (DISNMR, version 870101.1) and given by the expression 7= A3 + A2ei~T/Tl> in which A3 and A2 are constants and r represents the delay time between the 180°and 90°p ulses. For the calculation of Tl we used the relative intensities of the 13C signals at [12][13][14][15][16] different r values in an appropriate range; standard deviations were in the range ±0.007 to ±0.086 s.…”

“…Even though polystyrene-divinylbenzene is the most predominantly employed polymeric support for the stepwise peptide synthesis, many investigators consider that this carrier is probably not the most appropriate polymer for this purpose.22"24 Among the most interesting approaches to overcome the shortcomings ascribed to the cross-linked polystyrene resins, the introduction of the soluble poly(oxyethylene)11 and the graft copolymer poly-(oxyethylene-polystyrene)-DVB as polymeric supports merit particular attention. 12,13,25,26 To investigate the suitability of graft copolymers and poly(oxyethylene) in comparison with cross-linked polystyrene, several studies have been initiated. We present herein the use of 13C spin-lattice relaxation time measurements to study the molecular motion of the peptide attached to these macromolecules.…”

Peptide synthesis containing a B-cell and a T-cell epitope on dextran beads and evaluation of humoral response against bead-peptide construct

“…Such applications include solid-phase binding studies in an ELISA format, resin screening of peptide libraries, isolation and purification of peptide acceptors on affinity resins [14]. Besides, peptide synthesis on polymeric adjuvants offers a direct way to vaccination [15]. Up to now, peptides synthesized on dextran beads have not been used as immunogen.…”

Molecular Solvation and Mobility in Polymer/Liquid Interphases. A Fluorescence Study on Polystyrene−Poly(ethylene glycol) Microbeads

“…polystyrene (PS) prepared in the presence of small amounts of 1,4-divinylbenzene (DVB), which are grafted with chains of linear polymers, e.g. poly(ethylene glycol) (PEG). − The free ends of PEG can be modified with various functional y-groups. Several types of these flexible and geltype polymers (“Tentagel” ≡ TG) are available with bead diameters of d = 10 -3 −1 mm…”

“…poly(ethylene glycol) (PEG). [1][2][3][4] The free ends of PEG can be modified with various functional y-groups. Several types of these flexible and geltype polymers ("Tentagel" ≡ TG) are available with bead diameters of d ) 10 -3 -1 mm.…”