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Serine Hydroxymethyl Transferase from Streptococcus thermophilus and L ‐Threonine Aldolase from Escherichia coli as Stereocomplementary Biocatalysts for the Synthesis of β‐Hydroxy‐α,ω‐diamino Acid Derivatives
Author(s) -
Gutierrez Mariana L.,
Garrabou Xavier,
Agosta Eleonora,
Servi Stefano,
Parella Teodor,
Joglar Jesús,
Clapés Pere
Publication year - 2008
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200800031
Subject(s) - diastereomer , chemistry , aldolase a , threonine , hydroxymethyl , serine , glycine , stereochemistry , stereoselectivity , amino acid , organic chemistry , biochemistry , enzyme , catalysis
A novel serine hydroxymethyl transferase from Streptococcus thermophilus (SHMT) and a L ‐threonine aldolase from Escherichia coli ( L TA) were used as stereocomplementary biocatalysts for the aldol addition of glycine to N ‐Cbz amino aldehydes and benzyloxyacetaldehyde (Cbz=benzyloxycarbonyl). Both threonine aldolases were classified as low‐specific L ‐ allo ‐threonine aldolases, and by manipulating reaction parameters, such as temperature, glycine concentration, and reaction media, SHMT yielded exclusively L ‐ erythro diastereomers in 34–60 % conversion, whereas L TA gave L ‐ threo diastereomers in 30:70 to 16:84 diastereomeric ratios and with 40–68 % conversion to product. SHMT is among the most stereoselective L ‐threonine aldolases described. This is due, among other things, to its activity–temperature dependence: at 4 °C SHMT has high synthetic activity but negligible retroaldol activity on L ‐threonine. Thus, the kinetic L ‐ erythro isomer was largely favored and the reactions were virtually irreversible, highly stereoselective, and in turn, gave excellent conversion. It was also found that treatment of the prepared N ‐Cbz‐γ‐amino‐β‐hydroxy‐α‐amino acid derivatives with potassium hydroxide (1  m ) resulted in the spontaneous formation of 2‐oxazolidinone derivatives of the β‐hydroxyl and γ‐amino groups in quantitative yield. This reaction might be useful for further chemical manipulations of the products.

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