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

N. V. Ignatov¹ and F. F. Litvin^1,2

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.

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