[A prephenate dehydratase from Flavobacterium devorans stimulated by aromatic amino acids (author's transl)].

Isolation and properties of prephenate dehydratase from Flavobacterium devorans r are described. The enzyme was enriched 43-fold by ammonium sulfate precipitation, by gel chromatography on ultrogel ACA-34 and by hydrophobic chromatography on decylagarose. The molecular weight was estimated to be 1.35 x 10(5). The enzyme was activated in 1mM solutions of L-tyrosine 4,4-fold, of L-phenylalanine 3.9fold and by L-tryptophan 1.9-fold in 0.02M Tris/HCl buffer at pH 7.7. The Km values were, when adding the activator, at L-tyrosine 1.5 x 10(-5) M, at L-phenylalanine 1.3 x 10(-5) M and at L-tryptophan 1 x 10(-5) M. Regulation of aromatic amino acid is discussed in connection with the prephenate dehydratase.