Chloroplasts isolated from kidney bean leaves are capable of phenolic compound biosynthesis

The homogenate and chloroplast fractions isolated from the leaves of 10-14-day-old kidney-bean (Phaseolus vulgaris L.) seedlings were incubated with C-14-L-phenylalanine for 30 min in the light, and the incorporation of radioactivity into phenolic compounds was determined. Label incorporation into phenolic compounds of the homogenate and chloroplast fractions amounted to 15-17 and 4-5% of the introduced radioactivity, respectively. The chloroplasts were about an order of magnitude higher than the homogenate in the specific radioactivity of phenolic compounds. Chloroplasts contained four flavonol glycosides (kaempferol and quercetin aglycones), which were the major components of soluble phenolic compounds of leaves. It was concluded that kidney-bean leaf chloroplasts were capable of performing phenolic compound biosynthesis.