Effect of Chloramphenicol on Light-Dependent Synthesis of Proteins and Enzymes of Leaves and Chloroplasts of Phaseolus vulgaris

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Abstract
Chloramphenicol partially inhibits formation of leaf and plastid protein that occurs when etiolated leaves of Phaseolus vulgaris var. Black Valentine are irradiated with white light. The accompanying increase in leaf ribulose-1, 5-di P carboxylase activity also is inhibited, but that of TPN glyceraldehyde-3-P dehydro-genase is not affected. Plastids from chloramphenicol-treated leaves do not carry out either cyclic photophosphorylation in the presence of phenazine methosulfate or Hill reactions with dichlorophenolindophenol, ferricyanide or TPN even though they contain chlorophyll. They photo-reduce O2 but not TPN when reduced 2,6-dichloroindophenol is provided. Chloramphenicol has no effect on the location of the red absorption band of leaves nor on the wavelengths at which action peaks for chlorophyll fluorescence occur. However, treated leaves have a greater fluorescence yield. The action of chloramphenicol can be explained as a selective inhibition of synthesis of particular proteins. Some plastid development is not affected. It was concluded that plastids of etiolated leaves lack 1 or more proteins needed for light-dependent formation of TPNH and ATP.