Peptide synthesis vessel

For reduction of resin 8, concerns about the possibility of traces of tin by-products contaminating subsequent assays led to the adoption of a different reduction procedure for library production.15 The tagged resins 8 are combined into one pool in a large peptide synthesis vessel, washed with methanol, filtered, and the resin left solvated. Separately, an aqueous solution of 0.5 M aqueous sodium hydrosulfite/0.5 M potassium carbonate is prepared and added to the resin (40ml/g of resin) and then the resin/solu-tion is bubbled with nitrogen at room temperature for 16 h. The resulting resin is washed with water, water/MeOH (1 1), MeOH, MeOH/NMP (1 1), NMP, DCM, MeOH, and ether, then filtered and dried overnight in vacuo prior to the next step. 

The protocols have been written as they would be carried out using a manual peptide synthesis vessel. Whilst it is appreciated that most scientists preparing peptides will be using automated peptide synthesizers, it is not possible, given the wide variation in operating procedures, to describe how such methods may be applied to individual instruments. Particular emphasis has been given here to those operations which are typically carried out off-instrument, such as first residue attachment and peptide-resin cleavage. 

Pre-swell the peptidyl-resin (1 mmol) with DCM in a manual peptide synthesis vessel, and then wash with DCM (3 times). 

Place the peptidyl resin (200 mg) in a peptide synthesis vessel. 

Place the peptidyl resin in a sintered glass funnel or manual peptide synthesis vessel. 

Place the peptidyl resin <0.1 mmol) in the peptide synthesis vessel and dry overnight at 40°C in vacuo. 

Solid-phase ssmthesis vessels, Sofid-phase s5mthesis glassware, peptide synthesis vessels, or combinatorial chemistry glassware —To find reaction vessels for manual SPPS... 

Manual synthesis Glass 10 mL peptide synthesis vessel with a three-way stopcock and vacuum adapter (Chemglass, Vineland, NJ). 

Weigh out and place the Boc-P-Ala-Pam resin into the peptide synthesis vessel or Quest reaction vessel. Typical syntheses are performed on 200-400 mg of resin, i.e., 0.05-0.1 mmol scale (to give 10-30 mg final product). 

A recent development in this context is the Liberty system introduced by CEM in 2004 (see Fig. 3.25). This instrument is an automated microwave peptide synthesizer, equipped with special vessels, applicable for the unattended synthesis of up to 12 peptides employing 25 different amino acids. This tool offers the first commercially available dedicated reaction vessels for carrying out microwave-assisted solid-phase peptide synthesis. At the time of writing, no published work accomplished with this instrument was available. 

Modern combinatorial chemistry involves a number of steps that begin with the creation of a library of molecules that are closely related in structure. The library can be created in two ways (a) parallel synthesis, which is simultaneous synthesis of numerous products in separate discrete reaction vessels (b) combinatorial synthesis, of numerous reactions within one single reaction vessel followed by separations. The initial successes in parallel synthesis have been in solid peptide synthesis of proteins, which was based on Merrifield s solid-phase peptide synthesis. 

The sequence of solid-phase assembly and cyclization reactions used to prepare the bis(Ampa)-bridged peptide 31 is summarized in Scheme 19. All solid-phase procedures were performed in a standard, custom-built, 200-mL capacity, manual peptide synthesis reaction vessel. 165 ... 

In the reaction vessel of a Beckman 990 Peptide Synthesizer was placed 0.8 g (0.8 mmol) of benzhydrylamino-polystyrene-divinylbenzene resin (Lab Systems, Inc.) as described by Rivaille, supra. Amino acids were added sequentially to this resin by means of the usual methods of Boc-strategy of peptide synthesis on above copolymer. 

Glass peptide synthesis reaction vessel (Peptides International). 

Besides performing multiple syntheses in parallel, the accelerating of reaction rates may also achieve the same result— production of multiple peptides in the same time period. CEM (http //www.cem.com) has employed microwave irradiation to shorten both coupling and deprotection times. Their synthesizer, Odyssey (Fig. 7), achieves one cycle of peptide synthesis (Fmoc-based) in less than 10 min and is theoretically capable of the synthesis of 12 peptides in a row. However, for each new peptide the reaction vessel has to be cleaned and new batch of resin has to be transferred into it. This step raises concerns with the authors of this review about the possibility of cross-contamination. 

Probably the one greatest advantage of SPPS is that all of the synthetic operations are carried out in a single vessel after addition of the resin carrying the first (C-terminal) protected amino acid. Thus, the many manipulations of peptide synthesis in solution, with conconoitant losses of material, are eliminated. Vessels for SPPS must ... 

In batch SPPS (solid-phase peptide synthesis), the resin is contained in a vessel, usually equipped for bottom filtration. After a washing solvent or a reagent is added, the resin is mixed and the solvent or reagent is removed by filtration. Batch synthesizers use a variety of methods to mix the resin the wrist-action shaker, vortex mixing, nitrogen bubbling, or overhead stirring. 

A special case of parallel synthesis is the spatially addressable synthesis pioneered by Fodor et al. [17,18] in 1991. Here, each member of the library is synthesized at a specific location on a functionalized silica wafer rather than on resin beads in separate reaction vessels. This approach, based initially upon solid-phase peptide synthesis and semiconductor photolithographic techniques by using photolabile amino protecting groups, allows the synthesis of combinatorial libraries containing about 50000 compounds localized to a 50 pm square site on a silica wafer ( library on a chip ). 

For a 0.1 mmol synthesis, place 141 mg Rink Amide AM resin (substitution level 0.71mmol/g) in the peptide synthesis reaction vessel. Place the reaction vessel in one of the positions of the synthesizer. Add 2.5 mL DMF to swell the resin. Flush with nitrogen to form a suspension of resin for 30min (see Note 17). Drain off DMF. 

In 1985, R. Houghten reported on peptide synthesis carried on a resin sealed in porous polypropylene packets [11], The pore size of the polypropylene mesh (74 pm) allows for free access of chemicals to and from the contained resin. Each packet or tea bag can be individually labeled to identify the peptide synthesized on the entrapped polymer. Many tea bags can be combined in the same reaction to carry out common synthetic steps, such as washing and deprotection. The packets are sorted in separate reaction vessels according to the specific amino acid that will be coupled next. Cleavage, depending on the amount of used resin, can be carried out in separate vessels or in a 96-well microtiter plate with 2-mL well volume. In the original paper [11], 248 different tridecapeptides were synthesized in 10- to 20-mg quantities and characterized in less than four weeks. 

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