regulation of aromatic amino acid biosynthesis in amino acid liberating mutant strains of Anabaena variabilis

• Published in: Archives of microbiology Vol. 150; no. 3; pp. 272 - 277
• Main Authors: Niven, G.W, Kerby, N.W, Rowell, P, Stewart, W.D.P
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 01-07-1988; Berlin
• Subjects: 3-deoxy-D-arbinoheptulosonate-7-phosphate synthase; amino acids; Anabaena variabilis; anthranilate synthase; aromatic acids; Bacteriology; Biological and medical sciences; biosynthesis; control; Freshwater; Fundamental and applied biological sciences. Psychology; Metabolism. Enzymes; Microbiology; mutants; Regulation(control); Enzyme; Phospho-2-keto«-3-»deoxy-heptonate aldolase; Aminoacid; Cyanobacteria; Bacteria; Biosynthesis; Aromatic compound; Metabolism; Anabaena variabilis; Release
• ISSN: 0302-8933; 1432-072X
• DOI: 10.1007/BF00407791

Mutant strains of Anabaena variabilis which are resistant to the tryptophan analogue, 6-fluorotryptophan, liberated a wide range of amino acids although none liberated tryptophan in detectable quantities. Four strains (FT-7, FT-8, FT-9, FT-10) produced predominantly alanine together with small amounts of phenylalanine and tyrosine, strain FT-2 liberated mainly phenylalanine and tyrosine and strain FT-6 liberated mainly glutamate, NH super(+) sub(4) and several unidentified ninhydrin-positive compounds. Two forms of 3-deoxy-D-arbinoheptulosonate 7-phosphate (DAHP) synthase were identified in the parent strain, a tyrosine-sensitive form and a phenylalanine-sensitive form. In strains FT-2 and FT-6 the phenylalanine-sensitive enzyme was not detected and in strain FT-7 it was apparently deregulated with respect to inhibition by phenylalanine. No deregulation of anthranilate synthase was observed but mutant strains were found to have higher specific activities of this enzyme than the parent strain.