Broad-range alanine

A production method for the manufacture of cysteine by fermentation has been developed by Wacker Chemie. Building on this technology, an engineered E. coli strain overexpressing the enzyme O-acetylserine sulfhydrylase, which accepts a broad range of substrates, was used to produce a number of unnatural amino acids. This included triazole-1-yl-alanine, (S)-hydroxyethyl cysteine and phenylselenocysteine, which were prepared by feeding fermentations with unnatural precursor molecules (Figure 11.44) [287].These novel unnatural amino acids may prove useful for the synthesis of combinatorial (peptide) libraries. 

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