Peptides play a very important role in organisms, involving hormones, nerves, cell growth, reproduction and other aspects, and have nutritional, regulatory, antiviral and other functions. Since Merrirield invented the solid phase peptide synthesis method in 1963, the solid phase peptide synthesis method, especially the Fmoc method, has become the conventional method of peptide synthesis with its outstanding advantages of time-saving, labor-saving, easy automation and easy popularization, and has expanded to other organic fmoc-osu fields such as nucleotide synthesis

Solid phase synthesis of peptides:

In the solid phase peptide synthesis, the amino acid should be connected with the solid phase carrier first. The efficiency of this step directly affects the connection reaction between the subsequent amino acids, and ultimately affects the yield and purity of the target product. The connection methods of Fmoc protection amino acid and hydroxy resin mainly include acyl chloride method and activation ester method, and the reaction time is long (about 20h), Low connection efficiency (30%~80%)

Acyl chloride method vs activated ester method

Since the cost of solid phase carrier in peptide synthesis generally accounts for 20%~40% of the synthesis cost, such an inefficient connection method will inevitably increase the cost of synthesis for large-scale synthesis. We have respectively adopted the acyl chloride method and the activated ester method to select the largest amount of hydroxyl resin - Wang resin, and studied the connection reaction of 20 kinds of Fmoc-amino acids with hydroxyl resin, Explore a process route for efficient connection of Fmoc amino acid and Wang resin

Effect of solvent:

Solvents have a great influence on the connection efficiency. Compared with strong polar solvents DMF and NMP, weak polar solvents DCM and THF have higher connection efficiency between amino acids and resins. This is because weak polar solvents have good swelling property for resins, which is conducive to the contact between amino acids and hydroxyl functional groups on resins, and in weak polar solvents, amino acids are more active after being activated by acyl chloride, So as to speed up the esterification reaction

3 suggestions for improving reaction efficiency

(1) An economical and efficient connection process between Fmoc-amino acid and hydroxy resin was explored by using acyl chloride method and activated ester method. The connection efficiency can reach more than 80%

(2) Compared with the activated ester method, the acyl chloride method has the advantages of fast reaction rate, simple operation and high connection efficiency. It is a better method for the connection reaction of Fmoc-amino acid and hydroxyl resin

(3) The connection efficiency of Fmoc-Arg (Pbf) - OH in the two methods is not high, mainly because the steric hindrance of this amino acid is large and it is difficult to approach the solid carrier. The reaction solvent and reaction time have great influence on the connection efficiency, while the molar ratio of amino acid and resin has little influence on the connection efficiency; Using weak polar solvent DCM, the molar ratio of amino acid to resin is 3, the reaction time is 20 h, and the connection efficiency is close to 80%

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Article from custom peptide synthesis company in China-Omizzur