We synthesised analogues of diphosphoinositol polyphosphates (PP-InsPs) in which the diphosphate is replaced by an α-phosphonoacetic acid (PA) ester. Structural analysis revealed that 5-PA-InsP(5) mimics 5-PP-InsP(5) binding to the kinase domain of PPIP5K2; both molecules were phosphorylated by the enzyme. PA-InsPs are promising candidates for further studies into the biology of PP-InsPs.

Diadenosine pentaphosphate and diadenosine hexaphosphate have been isolated in human platelets and have been postulated to play an important role in the control of vascular tone. Here we describe the isolation and identification of diadenosine heptaphosphate from human platelets. Dinucleoside polyphosphates were concentrated by affinity chromatography from a nucleotide-containing fraction from ...

The findings presented here originally arose from the suggestion that the synthesis of dinucleoside polyphosphates (Np(n)N) may be a general process involving enzyme ligases catalyzing the transfer of a nucleotidyl moiety via nucleotidyl-containing intermediates, with release of pyrophosphate. Within this context, the characteristics of the following enzymes are presented. Firefly luciferase (E...

Multiple inositol polyphosphate phosphatase (Minpp1) metabolizes inositol 1,3,4,5,6-pentakisphosphate (InsP(5)) and inositol hexakisphosphate (InsP(6)) with high affinity in vitro. However, Minpp1 is compartmentalized in the endoplasmic reticulum (ER) lumen, where access of enzyme to these predominantly cytosolic substrates in vivo has not previously been demonstrated. To gain insight into the ...

Heat treatment is a simple technique for releasing polyphosphate (polyP) from microbial cells. We investigated the ultrastructural alterations of polyP granules (PPGs) in response to heat treatment at 70 degrees C using a polyP-accumulating phoU mutant of Escherichia coli as a model organism. Electron microscopic and energy-dispersive X-ray analysis suggested concurrent occurrence of PPG degrad...

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