Effect of PAN on Certain Photosynthetic Reactions

Abstract

The effect of the atmospheric oxidant, peroxyacetyl nitrate (PAN) on photosynthetic phosphorylation, NADP plus reduction, and CO/sub 2/ fixation by chloroplasts prepared from spinach and bean plants has been studied. When this gaseous oxidant was passed through reaction mixtures in the light, inhibition of the photosynthetic reactions occurred. Inhibition in ATP and NADPH formation and the fixation of C-1402 was prevented by the addition of ascorbate to the reaction mixture. Also NADP plus reduction was maintained by adding either excess photosynthetic pyridine nucleotide reductase (PPNR) or heat inactivated PPNR preparations. Gassing the individual components, chloroplasts or PPNR in the light or dark prior to their use in a complete reaction, did not cause inhibition. 14 references, 1 figures, 8 tables.