INFLUENCE OF CYTOKININS ON THE BIOSYNTHESIS OF LIGHT-HARVESTING CHLOROPHYLL-A/B PROTEINS IN TOBACCO CELL-SUSPENSIONS - DETECTION BY RADIOIMMUNOLOGICAL ASSAY

A radioimmunoassay for the light-harvesting chlorophyll a/b proteins (LHCP) was realized in order to estimate the amounts of LHCP in total proteins of tobacco cell suspensions, cultivated in the presence of kinetin or without cytokinin. This assay allowed qualitative and quantitative detection of LHCP and its cytosolic precursors (pLHCP). In the absence of cytokinin, very little LHCP or immuno-cross-reacting material was present in total cell proteins. A very tight correlation was observed between the rates of chlorophyll appearance and LHCP net synthesis during the cell growth cycle. These experiments suggested either that, in the absence of cytokinin, LHCP was unstable and very rapidly turned-over or that the hormone controlled the presence of LHCP in thylakoids by acting on some step(s) of the primary sequence biosynthesis.