THE G4 GENE OF ARABIDOPSIS-THALIANA ENCODES A CHLOROPHYLL SYNTHASE OFETIOLATED PLANTS

The gene coding for a putative chlorophyll synthase gene (G4) from Ara bidopsis thaliana was amplified by the polymerase chain reaction and c loned into the expression vector pQE-31. Lysates of bacteria (E. coli) that had been transformed with this construct were used for in vitro enzymatic assays. The chlorophyll synthase catalyzed esterification of chlorophyllides a and b at the same rate but preferred geranylgeranyl -PP over phytyl-PP. This corresponds to the enzyme specificity previou sly described for etiolated plants and differed from that of green pla nts.