Introduction topeptide synthesis The Merrifield peptide synthesis mechanism, pioneered by Nobel laureate Bruce Merrifield, revolutionized the field by introducing solid-phase peptide synthesis (SPPS)作者：O Al Musaimi·2025—Building upon the one-bead, one-compound concept, this approach enables thesimultaneous synthesis of multiple peptides on a single bead, .... This method involves building a peptide chain while it's covalently attached to an insoluble polymer support, typically in the form of small beads.Schematic representation of Merrifield solid-phase peptide ... This approach allows for the sequential addition of amino acids, with excess reagents and by-products being easily washed away at each step, streamlining the synthesis process and enabling the creation of complex peptides. The core of the Merrifield mechanism lies in the strategic attachment of the C-terminal amino acid to a solid support, followed by iterative cycles of deprotection and coupling.
The initial and critical step in the Merrifield mechanism is anchoring the first amino acid, specifically its C-terminus, to a solid support. This support is usually a crosslinked polystyrene resin, often functionalized with a linker molecule.Merrifieldand D. W. ... Within the experimental error of about 5% it was found that the diimide method caused no racemization in thesynthesisof the ... This linker creates an ester linkage, which is designed to be more easily cleaved than the peptide bonds that will subsequently be formed. The choice of resin and linker is crucial for the efficiency and success of the overall synthesis. This immobilization on a solid phase, typically a Merrifield resin, ensures that the growing peptide chain remains in place throughout the numerous reaction and washing steps作者：I Hargittai·2021—His idea was to start the synthesis of a peptideattaching the first amino acidto a solid support that was insoluble in all the solvents used ....
Following the attachment of the first amino acid, the Merrifield peptide synthesis mechanism proceeds through a series of repetitive cycles to elongate the peptide chain. Each cycle involves two primary stages: deprotection and coupling.Bruce Merrifield (1921–2006)
First, the N-terminal protecting group of the anchored amino acid is removed. This deprotection step is essential to expose the free amino group, making it available for the next reaction. Common protecting groups, such as tert-butyloxycarbonyl (Boc) or fluorenylmethyloxycarbonyl (Fmoc), are employed and must be chosen carefully based on their stability during subsequent coupling steps and ease of removal without damaging the growing peptide chain or the solid support.
Second, the next protected amino acid in the desired sequence is introduced. This amino acid, with its N-terminus protected and its carboxyl group activated, is then coupled to the free amino group of the growing peptide chain. This peptide coupling reaction forms a new amide (peptide) bond. Various coupling reagents and strategies are used to facilitate this reaction efficiently and minimize racemization, ensuring the stereochemical integrity of the amino acids. The reaction often proceeds via an SN2 mechanism, where the deprotected amino group attacks the activated carboxyl group.
A key advantage of the Merrifield mechanism is the ease of purification at each stage. After each deprotection and coupling step, the solid support, with the attached peptide, is thoroughly washed with appropriate solvents.Bruce Merrifield centennial: pioneer of chemical synthesis on ... This washing process effectively removes any unreacted reagents, excess amino acids, and soluble by-products.作者：B Merrifield·1997·被引用次数：247—This new technique is proving to be of great practical importance in rapid drug discovery ofpeptide,peptidemimetic, and nonpeptide compounds. This efficient removal of impurities is what distinguishes solid-phase synthesis from traditional solution-phase methods, where purification can be cumbersome and lead to significant product loss. The ability to simply filter the solid support allows for the retention of the peptide while discarding unwanted materials.
Once the complete peptide sequence has been assembled on the solid support, the final step involves cleaving the peptide from the resin.Bruce Merrifield - Nobel Lecture This cleavage is typically achieved using a strong acid, such as trifluoroacetic acid (TFA), which breaks the ester linkage between the peptide and the solid support. Simultaneously, any remaining side-chain protecting groups are also removed. The choice of cleavage cocktail is critical to ensure efficient release of the intact peptide while minimizing degradation or side reactions. After cleavage, the peptide is then precipitated, filtered, and further purified, often using techniques like High-Performance Liquid Chromatography (HPLC), to yield the final desired peptide product.
The Merrifield peptide synthesis mechanism's robustness and amenability to automation have made it an indispensable tool in biochemistry, medicine, and drug discovery, enabling the synthesis of peptides for research, therapeutic applications, and diagnostic purposesThe ester linkage that connects thepeptideto the resin, like most esters, is more easily cleaved than thepeptide(amide) bonds. The particular ester linkage ....
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