Untersuchungen der Tryptophan- und Anthranilsäure-Biosynthese in Hansenula henricii
1983; Elsevier BV; Volume: 178; Issue: 8 Linguagem: Inglês
10.1016/s0015-3796(83)80078-x
ISSN0015-3796
Autores Tópico(s)Chemical Reactions and Isotopes
ResumoThe cell pools of tryptophan and anthranilic acid and the levels of the enzymes of aromatic amino acid biosynthesis have been determined in Hansenula henricii Hg 48-2. The in vivo biosynthesis of tryptophan and anthranilic acid appears to be controlled primarily by feedback inhibition of the anthranilate synthase by tryptophan. The flux through the pathway is adjusted also by the lowering of concentration of anthranilate synthase and tryptophan synthase during the growth. The relative contributions of these 2 mechanisms to the control in vivo were analyzed. The other enzymes are present in excess. These exceeded the rate of consumption of the aromatic amino acids on minimal medium by a factor of 2-11. Our results suggest that the presence of required metabolites may be also an instrument for the specific regulation of the flux through the tryptophan pathway.
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