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In this task, you are given an abstract of article. Your task is to generate title for this article. Preferred titles are under thirty words.

Threonine can be used aerobically as the sole source of carbon and energy by mutants of Escherichia coli K-12. The pathway used involves the conversion of threonine via threonine dehydrogenase to aminoketobutyric acid, which is further metabolized by aminoketobutyric acid ligase, forming acetyl coenzyme A and glycine. A strain devoid of serine transhydroxymethylase uses this pathway and excretes glycine as a waste product. Aminoketobutyric acid ligase activity was demonstrated after passage of crude extracts through Sephadex G100.
Output:
Threonine as a carbon source for Escherichia coli.