title: Continuous enzymatic production of peptide precursor in aqueous/organic biphasic medium.
abstract: N-(benzyloxycarbonyl)-L-aspartic acid (Z-L-Asp) has generally been used as a carboxyl substrate for the enzymatic synthesis of a precursor of aspartame (synthetic sweetener); however, alternative inexpensive protection groups have been in demand for lowering the total cost of its industrial-scale production. A formyl group (F-) was found to be a more desirable protecting group for the N-terminus of amino acid derivatives due to its low cost of preparation, introduction, and removal. The yield of F-AspPheOMe (N-formyl-L-aspartyl-L-phe- nylalanine methylester), however, was found to be <10% in a conventional aqueous medium. We found that F-L-Asp and L-PheOMe were partitioned mainly to the aqueous phase in an aqueous/organic biphasic medium, whereas F-AspPheOMe partitioned to the organic phase, especially when some extracting agents were added. In this study, simultaneous operation of an enzymatic reaction and a product separation by liquid-liquid extraction was thus applied to the F-AspPheOMe synthesis. We succeeded in synthesizing F-AspPheOMe continuously in an aqueous/tributylphosphate (TBP) biphasic medium with >95% yield, which was about tenfold higher than that in an aqueous monophasic medium.
authors.affiliation: Department of Chemical Engineering, Waseda University, 3-4-1 Ohkubo, Shinjuku-ku, Tokyo 169-8555, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Murakami
authors.forename: T
authors.initials: T
authors.lastname: Yoshida
authors.forename: S
authors.initials: S
authors.lastname: Hayashi
authors.forename: A
authors.initials: A
authors.lastname: Hirata
mesh_terms: D009930:Organic Chemicals; D010455:Peptides / Q000138:chemical synthesis*; D011498:Protein Precursors / Q000138:chemical synthesis* / Q000737:chemistry; D012997:Solvents; D014867:Water
chemical_list: D009930:Organic Chemicals; D010455:Peptides; D011498:Protein Precursors; D012997:Solvents; D014867:Water