Peptide polystyrene resins

The chloromethylated polystyrene resin used for Merrifteld solid-phase peptide synthesis is prepared by treatment of polystyrene with chloromethyl methyl ether and a Lewis acid catalyst. Propose a mechanism for the reaction. 

The peptide is removed from the polystyrene resin by means of hydrogen fluoride. The couplings were nearly complete by using a threefold excess of the N-protected tripeptide. A fractionation of the resulting oligotripeptide, however, has been performed. The folding behavior in water was much more pronounced than in the case of the polymers obtained by the old TEPP method13 . 

The pore structure of most cross-linked polystyrene resins are the so called macro-reticular type which can be produced with almost any desired pore size, ranging from 20A to 5,000A. They exhibit strong dispersive type interaction with solvents and solutes with some polarizability arising from the aromatic nuclei in the polymer. Consequently the untreated resin is finding use as an alternative to the C8 and Cl8 reverse phase columns based on silica. Their use for the separation of peptide and proteins at both high and low pH is well established. 

Polystyrene resin with a hydroxymethylphenoxy linker (Wang resin)1 was originally developed for solid-phase peptide synthesis... 

FIGURE 5.8 Relative volumes of a polystyrene resin and a peptide-resin adduct in the presence or absence of solvent molecules. The values are for a peptide of 40 residues (molecular weight = 5957 daltons), the first residue loaded at 0.95 mequiv/g of resin, giving a peptide to resin ratio of 4 1 by weight after assembly.15... 

RB Scarr, MA Findeis. Improved synthesis and aminoacylation of p-nitrobenzophe-none oxime polystyrene resin for solid-phase synthesis of protected peptides. Pept Res 3, 238, 1990. 

Synthesis. The synthesis of cyclo retro enantlcxner 6 Is outlined in Scheme 1. Compounds 4, 5, 7> and 9 were prepared by an analogous route. Initially, a protected linear hexapeptide was prepared by solid phase synthesis on 2% crossllnked polystyrene resin beginning with a protected lysine resin. The peptide was then removed from the polymer by hydrazlnolysis. Cycllzatlon was... 

The peptide is synthesized on a derivatized solid support, often a polyamide or polystyrene resin, and synthesis proceeds from C-terminus to N-terminus. The linker group, which provides the link between the resin and the peptide... 

The nature of the polymer support is of great importance for a successful peptide synthesis. One that is widely used is a cross-linked polystyrene resin... 

Membrane polymeric materials for separation applications are made of polyamide, polypropylene, polyvinylidene fluoride, polysulfone, polyethersulfone, cellulose acetate, cellulose diacetate, polystyrene resins cross-linked with divinylbenzene, and others (see Section 2.9) [59-61], The use of polyamide membrane filters is suggested for particle-removing filtration of water, aqueous solutions and solvents, as well as for the sterile filtration of liquids. The polysulfone and polyethersulfone membranes are widely applied in the biotechnological and pharmaceutical industries for the purification of enzymes and peptides. Cellulose acetate membrane filters are hydrophilic, and consequently, are suitable as a filtering membrane for aqueous and alcoholic media. 

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