Nitrate reduction and the isolation of Nit- mutants in Hansenula polymorpha
Article Abstract:
Experiments were performed to isolate and characterize 10 complementation groups of Hansenula polymorpha mutants with reduced or undetectable nitrate reductase (NR) activities. Results showed that while NR activity is only induced in the presence of nitrate, the presence of ammonium or other reduced nitrogen sources inhibits this activity. These findings indicate that NR synthesis was dependent on the repression mechanisms produced by ammonium and the induction phenomena induced by nitrate.
Publication Name: Microbiology
Subject: Biological sciences
ISSN: 1350-0872
Year: 1998
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Cloning and characterization of the thiD/J gene of Escherichia coli encoding a thiamin-synthesizing bifunctional enzyme, hydroxymethylpyrimidine kinase/phosphomethylpyrimidine kinase
Article Abstract:
A study was conducted to analyze the cloning and preparation of the thiD/J gene of Escherichia coli supporting a thiamin-synthesizing bifunctional enzyme. The genes encode hydroxyethylthiazole kinase, hydroxymethylpyrimidine (HMP) kinase and phosphomethylpyrimidine kinase. The thiD product was determined from cell-free extracts. Results indicated that HMP kinase and HMP-P kinase are bifunctional enzyme encoded by the gene thiD/J.
Publication Name: Microbiology
Subject: Biological sciences
ISSN: 1350-0872
Year: 1999
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