Repression of the threonine synthetase system in Escherichia coli

Michael A. Savageau, John P. Steward

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Previous attempts to demonstrate repression in the system synthesizing threonine from homoserine by the addition of excess end-product gave negative results. By utilizing a mutant of Escherichia coli unable to synthesize homoserine from aspartic semialdehyde, we have shown that the threonine synthetase system is repressed when threonine is supplied at a rate that yields for the mutant organism a growth rate comparable to that of the wild-type organism in a similar medium. However, when threonine is in limited supply, this system is derepressed. That this system is normally repressed explains why earlier attempts to show repression by the addition of excess threonine were unsuccessful.

Original languageEnglish (US)
Pages (from-to)181-184
Number of pages4
JournalArchives of Biochemistry and Biophysics
Issue number1
StatePublished - 1970
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology


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