Different chain length specificity among three polyphosphate quantification methods

Ryo Ohtomo, Yoko Sekiguchi, Tomoko Kojima, Masanori Saito

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)

Abstract

Polyphosphate is ubiquitous among living organisms and has a variety of biochemical functions. Arbuscular mycorrhizal fungi have been known to accumulate polyphosphate as a key compound for their function. However, an enzymatic assay using polyphosphate kinase (PPK) reverse reaction, in which polyphosphate is converted to adenosine triphosphate (ATP) and quantified by luciferase assay, failed to detect accumulation of polyphosphate in some mycorrhizal root. When yeast exopolyphosphatase (PPX) was applied to these samples, a much higher polyphosphate level was detected than when the PPK assay was applied. Detailed analysis of substrate chain length specificity of these methods using polyphosphate chain length standards revealed that the PPX method was the most appropriate to detect short-chain polyphosphate. The average chain length of the shortest polyphosphate fraction that could be quantified with more than 50% efficiency was 3 for the PPX method and 38 for the PPK method. It was also suggested that the ratio of the PPK value to the PPX value may be useful as a simple and relative index to compare polyphosphate chain length distribution in different samples.

Original languageEnglish
Pages (from-to)210-216
Number of pages7
JournalAnalytical Biochemistry
Volume383
Issue number2
DOIs
Publication statusPublished - 2008 Dec 15

Keywords

  • Chain length
  • Polyphosphate
  • Polyphosphate exopolyphosphatase (PPX)
  • Polyphosphate kinase (PPK)

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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