95303-78-9

Upstream product

• 687-51-4 H-L-Leu-NH₂ 
• 1149-26-4 (S)-N-(benzyloxycarbonyl)valine 
• 10466-61-2 (2S)-amino-4-methylpentanamide hydrochloride 
• 203640-53-3 Z-L-Val carbamoylmethyl ester 
• 203640-52-2 Z-L-Val 2,2,2-trifluoroethyl ester 

Downstream Products

• 4817-93-0 (S)-methyl 2-((S)-2-(((benzyloxy)carbonyl)amino)-3-methylbutanamido)-4-methylpentanoate 

Relevant academic research and scientific papers

Enzymatic synthesis of activated esters and their subsequent use in enzyme-based peptide synthesis

Chemoenzymatic peptide synthesis is potentially the most cost-efficient technology for the synthesis of short and medium-sized peptides. However, there are still some limitations when challenging peptides, e.g. containing sterically demanding acyl donors, non-proteinogenic amino acids or proline residues, are to be synthesized. To remedy these limitations, special ester moieties have been used that are specifically recognized by the enzyme, e.g. guanidinophenyl, carboxamidomethyl (Cam) or trifluoroethyl (Tfe) esters, which, unfortunately, are notoriously difficult to synthesize chemically. Herein, we demonstrate that Cam and Tfe esters are very useful for Alcalase-CLEA mediated peptide synthesis using sterically demanding and non-proteinogenic acyl donors as well as poor nucleophiles, and combinations thereof. Furthermore, these esters can be efficiently synthesized by using the lipase Cal-B or Alcalase-CLEA. Finally, it is shown that the ester synthesis by Cal-B and subsequent peptide synthesis by Alcalase-CLEA can be performed simultaneously using a two-enzyme-one-pot approach with glycolamide or 2,2,2-trifluoroethanol as additive.

Broadening of the substrate tolerance of α-chymotrypsin by using the carbamoylmethyl ester as an acyl donor in kinetically controlled peptide synthesis

In the kinetically controlled approach of peptide synthesis mediated by α-chymotrypsin, the broadening of the protease's substrate tolerance is achieved by switching the acyl donor from the conventional methyl ester to the carbamoylmethyl ester. Thus, as a typical example, the extremely low coupling efficiency obtained by employing the methyl ester of an inherently poor amino acid substrate, Ala, is significantly improved by the use of this particular ester. Its ameliorating effect is observed also in the couplings of other amino acid residues such as Gly and Ser as carboxy components.

Remarkable effects of donor esters on the α-chymotrypsin-catalyzed couplings of inherently poor amino acid substrates

The extremely low efficiency during the α-chymotrypsin-catalyzed coupling of an inherently poor amino acid substrate, e.g., alanine, using the methyl ester as an acyl donor was significantly improved using esters such as the 2,2,2-trifluoroethyl or carbamoylmethyl ester. The ameliorating effect of the latter ester was especially significant.