Peptide synthesizers, multiple Phase Synthesizer

Centrifugation is a powerful technique allowing the parallel processing of an unlimited number of reaction compartments (101). The first centrifugal multiple peptide synthesizer, Compas 242 (76,102), utilized centrifugation for liquid removal from the functionalized cotton used as the solid support or from resin contained in polypropylene mesh bags (703). This system enabled the automation of tea-bag synthetic methodology. In principle, however, separation of solid and liquid phases was still accomplished by filtration. 

Lebl, M., Stierandova, A., Eichler, J., et al. (1992) An automated multiple solid phase peptide synthesizer utilizing cotton as a carrier. In Innovation and Perspectives in Solid Phase Peptide Synthesis (Epton, R., ed.). Intercept Limited, Andover, UK, pp. 251-257. 

In 1992, ACT replaced the Model 350 with the Model 396 Multiple Biomolecular Synthesizer. This instrument possesses two robotic arms, a variable speed orbital mixer, nitrogen assisted bottom filtration, a built-in ventilation system, protocols for both Fmoc and Boc synthesis and fully automated on-board cleavage for the Fmoc syntheses. It has reactor blocks of 8, 16, 40, and 96 wells for the synthesis of peptides from 5 pmol to 1 mmol. The Model 396 MBS also has a heater/cooler option for applications in solid-phase organic synthesis. 

Most synthetic methods for the generation of peptide libraries have been derived from various multiple parallel peptide synthesis techniques developed since 1984.bs-i l Consequently, the sohd supports used for hbrary synthesis are essentially the same as those used for multiple peptide synthesis. Standard divinylbenzene cross-linked polystyrene resins are typically used for hbraries that are cleaved from the resin and screened in solution.P Polyoxyethylene-grafted polystyrene resins,f l or acrylamide-polyoxyethylene copolymers, P on the other hand, are the sohd supports of choice for the synthesis of resin-bound peptide hbraries screened in sohd-phase binding assays.P Such resins are compatible with both organic solvents used for peptide synthesis, as well as aqueous buffers used in the bioassays. Various segmental supports previously employed for multiple peptide syntheses have also been utilized for the synthesis of peptide libraries, including polypropylene pins, PI cotton,t cellulose membrane,and glass shdes.P ... 

The main advantages of the OBOC method include 1) A large number (e.g., 10 —10 ) of peptides can be synthesized (Fig. lb) and screened rapidly and simultaneously by using either one or a combination of both on-bead and solution-phase assays, and 2) multiple peptide ligands with completely different motifs often can be identified in a single screening. This occm-rence is the opposite of the (convergent) iterative approach (see... 

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