Analytical Sciences

Abstract − Analytical Sciences, 29(11), 1095 (2013).

Colorimetric Determination of Pyrophosphate Anion and Its Application to Adenylation Enzyme Assay
Hajime KATANO, Hiro WATANABE, Masahiro TAKAKUWA, Chitose MARUYAMA, and Yoshimitsu HAMANO
Faculty of Biotechnology, Fukui Prefectural University, Eiheiji, Fukui 910-1195, Japan
A colorimetric pyrophosphate assay based on the formation and reduction of the 18-molybdopyrophosphate ([(P2O7)Mo18O54]4−) anion in an acetonitrile–water mixed solvent was modified and improved. The [(P2O7)Mo18O54]4− anion is precipitated from the acetonitrile–water solution containing MoO42− and HCl, and is re-dissolved in neat acetonitrile or propylene carbonate. This separation process decreases the interference by ATP, and prevents a yellow coloration of the reducing agent, ascorbic acid, due to excess Mo(VI) species. In the organic solvent, the [(P2O7)Mo18O54]4− anion is reduced to a more intense blue molybdopyrophosphate species. The application of the colorimetry to the assay of adenylation enzymes is also described in this note.