Skip to main content
Applied and Environmental Microbiology logoLink to Applied and Environmental Microbiology
. 1981 Sep;42(3):497–501. doi: 10.1128/aem.42.3.497-501.1981

Enzymatic Basis for Overproduction of Tryptophan and Its Metabolites in Hansenula polymorpha Mutants

Emmanuel O Denenu 1,, Arnold L Demain 1
PMCID: PMC244043  PMID: 16345845

Abstract

3-Deoxy-d-arabinoheptulosonate 7-phosphate (DAHP) synthetase and anthranilate synthetase are key regulatory enzymes in the aromatic amino acid biosynthetic pathway. The DAHP synthetase activity of Hansenula polymorpha was subject to additive feedback inhibition by phenylalanine and tyrosine but not by tryptophan. The synthesis of DAHP synthetase in this yeast was not repressed by exogenous aromatic amino acids, singly or in combinations. The activity of anthranilate synthetase was sensitive to feedback inhibition by tryptophan, but exogenous tryptophan did not repress the synthesis of this enzyme. Nevertheless, internal repression of anthranilate synthetase probably exists, since the content of this enzyme in H. polymorpha strain 3-136 was double that in the wild-type and less sensitive 5-fluorotryptophan-resistant strains. The biochemical mechanism for the overproduction of indoles by the 5-fluorotryptophan-resistant mutants was due primarily to a partial desensitization of the anthranilate synthetase of these strains to feedback inhibition by tryptophan. These results support the concept that inhibition of enzyme activities rather than enzyme repression is more important in the regulation of aromatic amino acid biosynthesis in H. polymorpha.

Full text

PDF
497

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Denenu E. O., Demain A. L. Derivation of Aromatic Amino Acid Mutants from a Methanol-Utilizing Yeast, Hansenula polymorpha. Appl Environ Microbiol. 1981 May;41(5):1088–1096. doi: 10.1128/aem.41.5.1088-1096.1981. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Doy C. H. Aromatic biosynthesis in yeast. II. Feedback inhibition and repression of 3-deoxy-D-arabino-heptulosonic acid 7-phosphate synthase. Biochim Biophys Acta. 1968 Jan 8;151(1):293–295. doi: 10.1016/0005-2744(68)90190-3. [DOI] [PubMed] [Google Scholar]
  3. Doy C. H., Cooper J. M. Aromatic biosynthesis in yeast. I. The synthesis of tryptophan and the regulation of this pathway. Biochim Biophys Acta. 1966 Oct 31;127(2):302–316. [PubMed] [Google Scholar]
  4. Fantes P. A., Roberts L. M., Huetter R. Free tryptophan pool and tryptophan biosynthetic enzymes in Saccharomyces cerevisiae. Arch Microbiol. 1976 Mar 19;107(2):207–214. doi: 10.1007/BF00446842. [DOI] [PubMed] [Google Scholar]
  5. Jensen R. A., Nester E. W. Regulatory enzymes of aromatic amino acid biosynthesis in Bacillus subtilis. I. Purification and properties of 3-deoxy-D-arabino-heptulosonate 7-phosphate synthetase. J Biol Chem. 1966 Jul 25;241(14):3365–3372. [PubMed] [Google Scholar]
  6. Levine D. W., Cooney C. L. Isolation and characterization of a thermotolerant methanol-utilizing yeast. Appl Microbiol. 1973 Dec;26(6):982–990. doi: 10.1128/am.26.6.982-990.1973. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Lingens F., Goebel W., Uesseler H. Regulation der Biosynthese der aromatischen Aminosäuren in Saccharomyces cerevisiae. 2. Repression, Induktion und Aktivierung. Eur J Biochem. 1967 May;1(3):363–374. doi: 10.1111/j.1432-1033.1967.tb00083.x. [DOI] [PubMed] [Google Scholar]
  8. Miozzari G., Niederberger P., Hütter R. Tryptophan biosynthesis in Saccharomyces cerevisiae: control of the flux through the pathway. J Bacteriol. 1978 Apr;134(1):48–59. doi: 10.1128/jb.134.1.48-59.1978. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. STICKLAND L. H. The determination of small quantities of bacteria by means of the biuret reaction. J Gen Microbiol. 1951 Oct;5(4):698–703. doi: 10.1099/00221287-5-4-698. [DOI] [PubMed] [Google Scholar]
  10. Turner J. R., Matchett W. H. Alteration of tryptophan-mediated regulation in Neurospora crassa by indoleglycerol phosphate. J Bacteriol. 1968 May;95(5):1608–1614. doi: 10.1128/jb.95.5.1608-1614.1968. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Applied and Environmental Microbiology are provided here courtesy of American Society for Microbiology (ASM)

RESOURCES