Sulfide inhibition of Photosystem II in cyanobacteria (blue-green algae) and tobacco chloroplasts

Aharon Oren*, Etana Padan, Shmuel Malkin

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

73 Scopus citations


The present study shows that in the presence of 600 nm light, sulfide acts as a specific inhibitor of photosynthetic electron transport between water and Photosystem II in the cyanobacteria Aphanothece halophytica and Synechococcus 6311 as well as in tobacco chloroplasts. In the presence of 600 nm light, sulfide affects the fast fluorescence transients as does a low concentration (10 mM) of hydroxylamine; the fluorescence yield decreases in the presence of either chemical and can be restored by the addition of 3-(3,4-dichlorophenyl)-1,1-dimethylurea. In chloroplasts, however, NH2OH, an electron donor at high concentrations (40 mM), relieves the sulfide effect. In the dark, sulfide affects the cyanobacterial fluorescence transients through decrease of oxygen tension. The fluorescence yield increases in a similar pattern to that observed under nitrogen flushing. Upon omission of sulfide in A. halophytica, the characteristic aerobic fluorescence transients return, consistent with the ease of alternation between oxygenic and sulfide-dependent anoxygenic photosynthesis in many cyanobacteria.

Original languageAmerican English
Pages (from-to)270-279
Number of pages10
JournalBiochimica et Biophysica Acta - Bioenergetics
Issue number2
StatePublished - 9 May 1979

Bibliographical note

Funding Information:
We wish to thank Mr. Shlomo Gershon for excellent technical assistance and Alexandra Mahler for help in the preparation of the manuscript. This study was supported by a grant from the Deutsche Forschungsgemeinschaft.


  • Chlorophyll fluorescence
  • Hydroxylamine (Cyanobacteria)
  • Photosystem II
  • Sulfide inhibition


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