Equipment for Solid Phase Peptide Synthesis HEADING_TITLE

Equipment for Manual Peptide Synthesis

Manual solid phase peptide synthesis can be carried out with standard laboratory glassware (i.e. round bottom flasks, sintered glass funnels, etc.) that has been treated with a silylating agent to prevent the resin from sticking to the glass surfaces.  Orbital shakers, wrist-action shakers or overhead mechanical stirrers may be used to agitate the resin suspensions.  Magnetic stirrers should not used because the resin beads can be damaged if they come between the stirring bar and the inside surface of the flask.  

While manual solid phase peptide synthesis can be performed with standard laboratory glassware, the repeated transfers required for filtering and washing in each amino acid coupling cycle are time consuming and may lead to resin loss from spillage or incomplete transfer of the resin.  A variety of specialized reactors for manual peptide synthesis are available.  Generally, they incorporate a glass frit for filtering and washing resin without transferring it from the vessel and ports for adding reaction solutions while maintaining an inert gas atmosphere.  Agitation is typically provided by a wrist-action shaker or inert gas bubbling.

Labmate Manual Peptide Syntheszer

LabMate Manual SPPS Synthesizer

Manual synthesizers like the AAPPTec LabMate™ incorporate reactors and a shaker into a convenient, compact unit.  Many manual synthesizers have a number of reactors that allow the user to prepare multiple peptides at the same time.  

Automated Solid Phase Peptide Synthesizers

Automated synthesizers may be classified as one of three types: batch synthesizers, continuous flow synthesizers, and library synthesizers.  Batch synthesizers such as the AAPPTec Focus XC™ can only prepare a few peptides at a time, but can prepare them on a large scale.  Depending on the design of the instrument, batch synthesizers can prepare peptides in up to kilogram scales.  These instruments use inert gas bubbling or mechanical agitation to provide mixing.

 

Focus XC

Focus XC Fully Automated Peptide Synthesizer

Until recently, all peptides synthesizers performed syntheses at ambient temperature.  Now many peptide synthesizer allow heating, either with microwaves or conventional means, during synthesis.  Focus XC™ series synthesizers also have optional cooling capabilities for performing reactions at reduced temperature.  This capability is useful when temperature sensitive materials, such as glyco amino acids, are utilized.  In addition, coupling at reduced temperature can reduce racemization of the activated residue.


Many batch synthesizers include some type of reaction monitoring, usually either photometrically or by conductivity.  Instead of using a preset time for a reaction, the reaction is allowed to continue until the measured parameter shows little or no change, indicating that the reaction has reached completion.  This feature optimizes the efficiency of peptide synthesis.  Slow reactions are not prematurely terminated resulting in deletion peptide impurities nor is time wasted when reactions are more rapid than expected.


Continuous flow synthesizers use pumps to recirculate the process solution through a column containing the resin. These synthesizers typically require special resins with low swelling.  Often some automatic monitoring method is used to track the progress of the reactions.  When the monitoring indicates the reaction is complete, the next process step is initiated. Since the reaction solution constantly flows through the resin, continuous flow synthesizers do not require a mechanical means of agitation.

Apex 396 peptide synthesizer

 Apex 396 Multiple Peptide Synthesizer


Library synthesizers like the AAPPTec Apex 396™ and Matrix 384™ are parallel synthesizers, preparing numerous peptides in small scale simultaneously.  The Apex 396 can prepare up to 96 individual peptides at once and the Matrix 384 can prepare up to 384 different peptides at a time.  Parallel synthesizers often are utilized to prepare peptide libraries for drug discovery, structure-activity (SAR) studies and epitope mapping.  Parallel synthesizers can also be used to prepare larger quantities of peptide by running parallel syntheses of the same sequence.

Titan 357 peptide synthesizer

Titan 357 Combinatorial Peptide Library Syntheiszer

 

The AAPPTec Titan 357™ is an example of a combinatorial library synthesizer utilizing the split-and-mix strategy developed by A. Furka.1  Each resin bead acts as a separate reactor producing a separate peptide.  Combinatorial synthesizers can prepare libraries containing millions of peptides in a single synthesis, albeit the peptides are produced as a mixture.  Combinatorial libraries are most useful in high throughput screening utilizing on-resin screening techniques.  Beads containing peptides of interest can be isolated and the peptides identified by sequencing.

 


 

Footnote

1 Furka, Á., Sebestyén, F., Asgedom, M., Dibó, G., Int. J. Peptide Protein Res., 1991, 37, 487-493.