Formation of inorganic pyrophosphate

Inorganic pyrophosphate as phosphate and energy donor in soluble systems 

Several enzymes using PPj as phosphoryl donor have been described in bacteria and parasitic amoebae [22-24]. In both Propionibacterium shermanii and the eukaryote Entamoeba histolytica, the enzyme PPi-phosphofructose dikinase has been found [39,40]. This enzyme uses PPj as the phosphoryl donor to fructose-6-phosphate instead of ATP  

The rate of this reversible reaction is virtually identical in both directions. The enzyme appears to play a major role in the glycolytic pathway of both P. shermanii 

Another enzyme that uses the energy of the PPj is the pyruvate, phosphate dikinase. This enzyme converts P-enolpyruvate to pyruvate, but unlike pyruvate kinase, which uses ADP as the phosphate acceptor yielding ATP and pyruvate. This enzyme uses AMP and in combination with PPj yields ATP, Pj and pyruvate  

The enzyme has been discovered in the leaves of topical grasses such as sugar cane [47], in the amoeba E. histolytica [48], in Bacteroides symbiosus [49], in P. shermanii [50], in Acetobacter xylinum [51] and in several photosynthetic bacteria including R. rubrum [52]. The dikinase appears to function in different directions in different organisms. For example in A. xylinum, P. shermanii, and in the C4 plants it functions in the direction of P-enolpyruvate formation. On the other hand, in E. histolytica and B. symbiosus, this enzyme provides a means of formation of pyruvate and ATP. 

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NRP) and adenosine triphosphate (ATP) with the formation of inorganic pyrophosphate (PP). ... 

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