Open AccessRegulation der Biosynthese der aromatischen Aminosäuren in Claviceps paspali
Author(s) -
Lingens F.,
Goebel W.,
Uesseler H.
Publication year - 1967
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1967.tb00157.x
Subject(s) - chorismate mutase , tryptophan , phenylalanine , biochemistry , tyrosine , enzyme , chemistry , aromatic amino acids , biology , amino acid
DAHP‐synthetase, chorismate mutase, prephenate dehydrogenase, prephenate dehydratase and anthranilate synthease were identified in extracts of Claviceps paspali mycelium. We were able to separate three DAHP‐synthetases, one sensitive to l ‐phenylalanine, one sensitive to l ‐tyrosine and one sensitive to l ‐tryptophan. The l ‐tryptophan sensitive isoenzyme provided the main part of the DAHP‐synthetase activity (about 60%). The inhibition due to l ‐tryptophan was not removed by l ‐tyrosine nor l ‐phenylalanine. Chorismic acid did not inhibit these enzymes. Chorismate mutase was inhibited by l ‐tyrosine and also by l ‐phenylalanine, though these inhibitions were only detected after purification of the enzyme, and even then the highly purified enzyme ( ca. 100‐fold) could not be separated into isoenzymes. The inhibition of the purified enzyme by l ‐tyrosine and l ‐phenylalanine could be removed entirely by l ‐tryptophan. Prephenate dehydratease was inhibited only by l ‐phenylalanine and it could not be activated by l ‐tyrosine nor l ‐tryptophan. Prephenate dehydrogenase showed an inhibiting effect by l ‐tyrosin only after purification. Anthranilate synthetase was not inhibited by l ‐tryptophan even after purification. Anthranilate synthetase was not inhibited by l ‐tryptophan even after purification. With the simultaneous additions of l ‐tyrosine, l ‐phenylalanine and l ‐tryptophan (in equal concentrations of 1 × 10 −3 M) no repression effects could be produced.