Site-Selected Chromophore Oxidation of Phytochrome with Tetranitromethane

Dave Farrens, Pill Soon Song, Wolfhart Rüdiger, Peter Eilfeld

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Chromophore oxidation using tetranitromethane was performed with 124 kDa, 59kDa, and 39kDa oat phytochrome in both photoreversible forms (Pr and Pfr). Kinetics and intermediates of oxidation were analyzed using a diode array spectrophotometer. A transient species (λmax = 580 and 505 nm) was observed exclusively from the Pfr (or Pbl in the case of 39 kDa phytochrome) forms of degraded phytochromes. This oxidation product was isolated by rapid size-exclusion HPLC. Comparison of its absorption spectrum with those of model compounds revealed a strong similarity to biladienes-a,b, indicating that the primary attack of tetranitromethane takes place at the methine bridge, predominantly at C-15. This is interpreted in terms of a different accessibility of carbon-15 of the chromophore in the Pr vs. Pfr form.

Original languageEnglish (US)
Pages (from-to)269-275
Number of pages7
JournalJournal of Plant Physiology
Issue number3
StatePublished - 1989
Externally publishedYes


  • Chromopeptides
  • Chromophore oxidation
  • Da
  • HPLC
  • HPLC
  • Oat (Avena sativa)
  • P660
  • Pbl
  • Pfr
  • Phytochrome
  • Pr
  • Pr form of 39 kDa phytochrome absorbing at around 660 nm
  • TNM
  • bleached form of phytochrome (formed instead of Pfr)
  • dalton
  • far-red absorbing form of phytochrome
  • high-pressure liquid chromatography
  • red absorbing form of phytochrome
  • tetranitromethane

ASJC Scopus subject areas

  • Physiology
  • Agronomy and Crop Science
  • Plant Science


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