Pure forms of the singlet oxygen sensors TEMP and TEMPD do not inhibit Photosystem II

: Hideg E, Deak Z, Hakala-Yatkin M, Karonen M, Rutherford AW, Tyystjarvi E, Vass I, Krieger-Liszkay A

Publisher: ELSEVIER SCIENCE BV

: 2011

: BBA - Bioenergetics

: BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS

: BBA-BIOENERGETICS

: 12

: 1807

: 12

: 1658

: 1661

: 4

: 0005-2728

DOI: https://doi.org/10.1016/j.bbabio.2011.09.009

In a recent article (Hakala-Yatkin and Tyystjarvi BBA 1807 (2011) 243-250) it was reported that the singlet oxygen spin traps 2,2,6,6-tetramethylpiperidine (TEMP) and 2,2,6,6-tetramethyl-4-piperidone (TEMPD) inhibit Photosystem II (PSII), the water oxidizing enzyme. 02 evolution, chlorophyll fluorescence and thermoluminescence were measured and were shown to be greatly affected by these chemicals. This work casts doubts over an earlier body of work in which these chemicals were used as spin traps for monitoring (1)O(2) production when PSII was inhibited by high light intensities. Here we show that these spin probes hardly affect PSII. We show that the commercial batches of TEMPD and TEMP used by Hakala-Yatkin and Tyystjarvi contained impurities and/or derivatives that inhibited PSII and caused the specific effects on fluorescence. Earlier work that used pure spin traps to measure (1)O(2) during photoinhibition, thus remains valid. However, concern must be expressed towards using these spin traps without proper controls. (C) 2011 Elsevier B.V. All rights reserved.