Polyphosphate-Glucose Phosphotransferase EC

This enzyme catalyses the phosphorylation of glucose using polyP or ATP as the phosphoryl donor  

The enzyme activity was not found in eucaryotes. The discovery of this enzyme was of the greatest significance for our understanding of the role of PolyPs it provided the first evidence of the possible function of PolyPs as a phosphate and energy donor without the nucleoside phosphate system. 

All of these observations suggest a hypothesis that PolyP was a precursor of ATP in bioenergetic processes at the earliest stage of evolution (Kulaev, 1971,1974). There might 

The above reaction was known many years ago (Komberg, 1950 Wang and Kaplan, 1954) and found both in procaryotes and eucaryotes. In Brevibacterium ammoni-agenes (Murata et al., 1979), Micrococcus luteus and Corynebacterium ammoniagenes (Fillipovich et al., 2000) phosphorylation of NAD using PolyP as a phosphate donor was revealed  

It has been established that in some bacteria one enzyme displays both activities (Kawai et al., 2000). An enzyme with both PolyP- and ATP-dependent NAD kinase activities was isolated from Micrococcus flavus. This enzyme is a dimer consisting of 34 kDa subunits. A gene Rvl 695 has been found in Mycobacterium tuberculosis and proposed to also be a PolyP-dependent NAD kinase. By cloning and expression in E. coli, Rvl695 was shown to encode PolyP/ATP-NAD kinase and was named as ppnk. The ppnk product, a recombinant PolyP/ATP-NAD kinase (Ppnk), was purified and characterized. This enzyme was a tetramer consisting of 35 kDa sub-units when expressed in E. coli. PolyP/ATP-NAD kinases of M. flavus and Ppnk of M. tuberculosis H37Rv phosphorylated NAD, using PolyP and nucleoside triphosphates as the phosphoryl donors (Kawai et al., 2000). 

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