Zeptomole Detection of an Enzyme by a Simple Colorimetric Method Kanako

Kanako Iha, Yuta Kyosei, Mayuri Namba, Daiki Makioka, Sou Yamura, Satoshi Watabe, Teruki Yoshimura, Etsuro Ito*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


An enzyme immunoassay, in which an enzyme (e.g., alkaline phosphatase, ALP) is conjugated with an antibody, is a precise and simple protein detection method. Precise measurements of enzymes at low concentrations allow for ultrasensitive protein detection. The application of a phosphorylated substrate to ALP, followed by using a dephosphorylated substrate in thionicotinamide-adenine dinucleotide cycling, provides a simple and precise quantification of ALP. We describe a protocol for detecting ALP at the zeptomole level using a simple colorimetric method.

Original languageEnglish
Pages (from-to)1469-1472
Number of pages4
JournalAnalytical Sciences
Issue number10
Publication statusPublished - 2021


  • Colorimetry
  • thio-NAD cycling
  • ultrasensitive ELISA
  • zeptomole

ASJC Scopus subject areas

  • Analytical Chemistry


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