Embden–Meyerhof–Parnas and Entner–Doudoroff pathways in Thermoproteus tenax: metabolic parallelism or specific adaptation?

Genome data as well as biochemical studies have indicated that – as a peculiarity within hyperthermophilic Archaea – Thermoproteus tenax uses three different pathways for glucose metabolism, a variant of the reversible EMP (Embden–Meyerhof–Parnas) pathway and two different modifications of the ED (Entner–Doudoroff) pathway, a non-phosphorylative and a semi-phosphorylative version. An overview of the three different pathways is presented and the physiological function of the variants is discussed.