Activation parameters of the blue shift (Shibata shift) subsequent to protochlorophyllide phototransformation

Research output: Contribution to journalArticle

12 Citations (Scopus)


The Shibata shift was analyzed in flash irradiated wheat (Triticum aestivum, L., cult. MV17) leaf homogenates in the pressure range of 0.1 to 500 MPa, at temperatures of 20, 30 and 40°C. The kinetics of the blue shift (called Shibata shift in case of intact leaves) was followed by repeated recording of fluorescence emission spectra after phototransformation. At 20°C, above 100 MPa, the blue shift slowed down remarkably. Two components of the blue shift could be distinguished, one was pressure-dependent and the other was almost pressure-independent. The pressure-independent component can be associated with minor conformational changes of the NADPH: protochlorophyllide oxidoreductase (POR) enzyme, followed by molecular movements of the newly formed chlorophyllide molecules. The calculated activation volume of the pressure-dependent component was 43±11 cm 3 mol-1 at 20°C. This value reflects major molecular reorganizations in the lipid system of the membrane and in the chlorophyllide-protein complexes, and corresponds to changes of the tertiary structure of proteins which can proceed directly or indirectly via structural changes of the membrane lipids. The process was inhibited by 300 and 400 MPa at 30 and 40°C, respectively. The activation volume reduced to 35±1.5 cm3 mol-1 at 40°C. The decrease of the activation volume with increasing temperature indicates that the blue shift requires loosened lipid structures. The activation energy of the blue shift (measured between 10 and 40°C at atmospheric pressure) was 100±20 kJ/mol, indicating that the structural change involves rearrangement of strong molecular interactions.

Original languageEnglish
Pages (from-to)130-138
Number of pages9
JournalBiochimica et Biophysica Acta - Proteins and Proteomics
Issue number1-2
Publication statusPublished - Sep 23 2003



  • Activation energy
  • Activation volume
  • Chlorophyllide
  • Protochlorophyllide
  • Shibata shift

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biophysics
  • Biochemistry
  • Molecular Biology

Cite this