Hoechst Aktiengesellschaft

Johann Then

Hans-Matthias Deger

Rudiger Marquardt

Susanne Grabley

Klaus Bartsch

Gerhard Wohner

Martyn K Robinson

Merten Schlingmann

Reinhold Keller

Werner Aretz

Klaus Sauber

Hartmut Voelskow

Martin Platen

Evelyn L Doherty

Andrew Doherty

L-tertiary-Leucine and L-phosphinothricine are obtainable by transamination of the corresponding keto acids as a precursor in the presence of amino acids as amino group donors. The reaction is preferably carried out with microorganisms or their transaminases.

Process for preparing L-tertiary-leucine and L-phosphinothricine by

Process for preparing L-tertiary-Leucine and L-phosphinothricine by

L-2-Amino-4-methylphosphinobutyric acid can be prepared by a racemate resolution in the presence of D-aminoacid and L-aminoacid transaminases by reaction with .alpha.-keto acids and amino-group donors. In particular, transaminases from Bacillus licheniformis and from Escherichia coli are used.

Process for the preparation of L-phosphinothricin using transaminases of

The ilvE gene from the strain E. coli ATCC 11303 is suitable for achieving overproduction of the coded aliphatic transaminase and thus for preparing the branched-chain amino acids leucine, isoleucine and valine from the corresponding keto precursors.

Cloning and use of the transaminase gene ilvE

The isolation of the tyrB gene contained in E. coli ATCC 11303 and its cloning onto a multicopy plasmid results in a 10-fold increase in the L-phenylalanine yield after the transformation of the starting strain with this plasmid.

Cloning and use of transaminase gene tyrB

L-Phenylalanine can be prepared using microorganisms belonging to the series comprising E. coli, Paracoccus denitrificans, Torula, Rhodotorula or Streptomyces after adaptation to phenylpyruvic acid, by amination with suitable sources of nitrogen. It is advantageous to employ the microorganism in the form of fixed cells.

Process for the preparation of L-phenylalanine

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Hofheim am Taunus, Germany

Johann Then