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The Entner–Doudoroff pathway (ED pathway) describes a pathway—a series of enzyme-catalyzed chemical reactions— that are active in bacterial primary metabolism, a pathway that catabolizes glucose to pyruvic acid using enzymes distinct either from those used in glycolysis or the pentose phosphate pathway (the latter two being most widely used in the Bacteria). The ED pathway was first reported by Michael Doudoroff and Nathan Entner from the Bacteriology Department at the University of California, Berkeley in 1952. Recent work on the Entner-Duodoroff pathway has shown that its use is not restricted to prokaryotes as was previously thought. Specifically, there is direct evidence that Hordeum vulgare utilizes the Entner-Doudoroff pathway. Use of the Entner Duodoroff pathway among other plants such as mosses and ferns is also probably widespread based on preliminary sequencing data analysis.
Distinct features of the Entner–Doudoroff pathway are that it:
Organisms that utilize the Entner-Doudoroff pathway
There are several bacteria that utilize Entner–Doudoroff pathway for metabolism of glucose and are unable to catabolize via glycolysis (e.g., therefore lacking essential glycolytic enzymes such as phosphofructokinase as seen in Pseudomonas). Genera in which the pathway is prominent include Gram-negative, as listed below, Gram-positive bacteria such as Enterococcus faecalis, as well as several in the Archaea, the second distinct branch of the prokaryotes (and the "third domain of life", after the prokaryotic eubacteria and the eukaryotes). Most organisms that use the pathway are aerobes, due to the low ATP yield per glucose molecule metabolised.
Examples of bacteria using the pathway are:
The Entner-Doudoroff pathway is present in many species of Archaea (caveat, see following), whose metabolisms "resemble... in [their] complexity those of Bacteria and lower Eukarya," and often include both this pathway and the Embden-Meyerhof-Parnas pathway of glycolysis, except most often as unique, modified variants.