ISSN print edition: 0366-6352
ISSN electronic edition: 1336-9075
Registr. No.: MK SR 9/7
2-Alkylsulphanyl-4-pyridinecarbothioamides — inhibitors of oxygen evolution in freshwater alga Chlorella vulgaris
Katarína Kráľová, František Šeršeň, Věra Klimešová, and Karel Waisser
Institute of Chemistry, Faculty of Natural Sciences, Comenius University, SK-842 15 Bratislava, Slovakia
Abstract: The inhibition of the oxygen evolution rate (OER) in Chlorella vulgaris by 2-alkylsulphanyl-4-pyridinecarbothioamides (APCTs; alkyl = methyl up to hexadecyl) was studied. APCTs were found to inhibit
photosynthetic electron transport (PET) which resulted in the inhibition of OER in algae. The inhibitory activity of APCTs
was highly dependent on the alkyl chain length of the 2-alkylsulphanyl substituent and the corresponding dependence showed
a bilinear course with the decyl derivative as being the most active inhibitor. Using EPR spectroscopy, the site of APCT action
in the algal photosynthetic apparatus was determined. It was confirmed that APCT interacted mainly with the D. intermediate,
i.e. with tyrosine radical (TyrD) occurring at the 161st position in D2 protein which is situated on the donor side of photosystem 2.
Keywords: alkyl length – Chlorella vulgaris – EPR spectroscopy – photosynthetic electron transport – inhibition – oxygen electrode
Full paper is available at www.springerlink.com.
Chemical Papers 65 (6) 909–912 (2011)