Phosphatases are known to play a crucial role in phosphate turnover in plants. However, the exact role of acid phosphatases in plants has been elusive because of insufficient knowledge of their in vivo substrate and subcellular localization. We investigated the biochemical properties of a purple acid phosphatase isolated from red kidney bean (Phaseolus vulgaris) (KBPAP) with respect to its subs...

Combinatorial expression of the various isoforms of diphosphoinositol synthases and phosphohydrolases determines the rates of phosphorylation/dephosphorylation cycles that have been functionally linked to vesicle trafficking, stress responses, DNA repair, and apoptosis. We now describe two new 19-kDa diphosphoinositol polyphosphate phosphohydrolases (DIPPs), named types 3alpha and 3beta, which ...

We have investigated the activity of naturally occurring high-performance liquid chromatography-purified diadenosine polyphosphates (Ap(n)A, n = 5-6), adenosine polyphospho guanosines (Ap(n)G, n = 5-6), and diguanosine polyphosphates (Gp(n)G, n = 5-6) under voltage-clamp conditions at recombinant rat P2X1-4 purinoceptor subtypes expressed in Xenopus laevis oocytes. At rP2X1 and rP2X3 receptors,...

Polyphosphate is ubiquitous and has a variety of biochemical functions. Among polyphosphate quantification methods, an enzymatic assay using Escherichia coli polyphosphate kinase (PPK), in which polyphosphate is converted to adenosine 5'-triphosphate and quantified by luciferase assay, is the most specific and most sensitive. However, chain-length specificity of the assay has not been analyzed ...

Live sporangiophores of Phycomyces blakesleeanus were centrifuged at 35,000 rpm . The cell contents sedimented into distinct layers, and each layer was studied with an electron microscope and with cytochemical methods . The following layers were found (their volumes and their densities are shown in Fig . 3) : 1 . polyphosphates ; 2 . polyphosphates and protein crystals ; 3 . glycogen ; 4 . yell...