Expression of the Escherichia coli catabolic threonine dehydratase in Corynebacterium glutamicum and its effect on isoleucine production

Article Abstract:

The catabolic or biodegradative threonine dehydratase of Escherichia coli is an isoleucine feedback-resistant enzyme that catalyzes the degradation of threonine to alpha-ketobutyrate, the first reaction of the isoleucine pathway. This enzyme was cloned and expressed in Corynebacterium glutamicum. It was observed that while the native threonine dehydratase of C. glutamicum was totally inhibited by 15 mM isoleucine, the heterologous catabolic threonine dehydratase expressed in the same strain was much less sensitive to isoleucine.

Escherichia coli, Microbial enzymes, Threonine

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Triggering glutamate excretion in Corynebacterium glutamicum by modulating the membrane state with local anaesthetics and osmotic gradients

Article Abstract:

The addition of local anaesthetics such as tetracaine and hypo-osmolarity increases glutamate excretion by Corynebacterium glutamicum cells. The excretion is specific, carrier mediated and independent of membrane changes. The tetracaine-induced glutamate excretion is similar to that caused by biotin limitation. The osmotic changes are insufficient to affect excretion by themselves. The effects of osmotic gradients and local anaesthetics on glutamate excretion are exchangeable and probably have a similar mode of action.

Physiological aspects, Observations, Glutamate, Anesthetics

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Purification and characterization of monovalent cation-activated levodione reductase from Corynebacterium aquaticum M-13

Article Abstract:

Monovalent cation-activated levodione reductase of Corynebacterium aquaticum M-13, not previously reported, is discussed. The reductase was isolated from a cell extract of the soil isolate C. aquaticum. The enzyme required certain cofactors, but catalyzed reversible oxidoreduction between actinol and levodione, activated by monovalent cations. The enzyme is in the short-chain alcohol dehydrogenase/reductase family.

Japan, Statistical Data Included, Enzymes, Oxidation-reduction reaction, Oxidation-reduction reactions, Cations

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