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Effect of Heavy Water (D2O) on Reactions of Chlorophyll Biosynthesis in Greening Plant Leaves

N. V. Ignatov1 and F. F. Litvin1,2

1Department of Physico-Chemical Biology, School of Biology, Lomonosov Moscow State University, Moscow, 119899 Russia; E-mail: ozrina@jnlbioch.bio.msu.su

2To whom correspondence should be addressed.

Submitted October 29, 1996.

Using the methods of luminescence and absorption spectroscopy we have shown that introduction of heavy water (D2O) into etiolated plant leaves leads to a complete blocking of the biosynthesis of the complexes of pheophytin contained in the reaction centers of PS II Chlde 684/676 -> [Pheo 679/675, Chl 675/668, Chl 671/668] and to a partial inhibition of the "Shibata shift" which is responsible for biosynthesis of the bulk of antenna chlorophyll. In the presence of D2O a dark conversion of the native form Chlde 684/676 into Chlde 690/680 has been found. An effect of deuterium oxide on other reactions of chlorophyll biosynthesis from chlorophyllide has not been found.

KEY WORDS: chlorophyll a biosynthesis, deuterium oxide, inhibition of chlorophyll biosynthesis, antenna chlorophyll, reaction center chlorophyll.