Nucleotide Activation of Threonine Deaminase from Escherichia Coli.

Serine and threonine desaminaes of Escherichia coli; activators for a cell-free enzyme.

Serine has been reported by many workers to be deaminated by a variety of bacterial cells and tissues, but this process was first studied in detail by Gale and Stephenson in 1938 (1). These workers followed the serine deaminase of Escherichia coli by measuring the release of ammonia by resting cell suspensions. The reaction proceeded anaerobically, thereby distinguishing it from the oxidative d...

Cooperative binding of the feedback modifiers isoleucine and valine to biosynthetic threonine deaminase from Escherichia coli.

Control of the regulatory enzyme threonine deaminase from Escherichia coli is achieved by isoleucine inhibition and valine activation. The mechanism by which these heterotropic effectors regulate the enzyme was investigated by measuring the binding of isoleucine and valine by spectroscopic, kinetic, calorimetric and equilibrium dialysis techniques. The addition of isoleucine or valine to threon...

On the role of pyridoxal phosphate for amp-dependent threonine deaminase of Escherichia coli.

Cysteine and growth inhibition of Escherichia coli: threonine deaminase as the target enzyme.

Cysteine has been shown to inhibit growth in Escherichia coli strains C6 and HfrH 72, but not M108A. Growth inhibition was overcome by inclusion of isoleucine, leucine, and valine in the medium. Isoleucine biosynthesis was apparently affected, since addition of this amino acid alone could alter the inhibitory effects of cysteine. Homocysteine, mercaptoethylamine, and mercaptoethanol inhibited g...

IS2 activates the ilvA gene of Pseudomonas cepacia in Escherichia coli.

The ilvA gene of Pseudomonas cepacia was expressed poorly in Escherichia coli. Insertion of IS2 upstream of the cloned gene dramatically increased its transcription, resulting in an 85-fold increase in threonine dehydratase (deaminase) specific activity. The results confirm earlier reports that IS2 promotes efficient expression of foreign genes in E. coli.