Evidence for in vivo Light-induced Synthesis of Ribulose-1,5-diP Carboxylase and Phosphoribulokinase in Greening Barley Leaves

Abstract

When actinomycin D, puromycin, streptomycin, chloramphenicol, and cycloheximide, known inhibitors of protein synthesis, were applied to leaves of intact seedlings or detached leaves of barley prior to their greening, the same general response resulted: the light-induced increase in activity of ribulose 1,5-diphosphate carboxylase was prevented while that of phosphoribulokinase was only partially suppressed; synthesis of chlorophyll was arrested. This is taken as preliminary evidence that de novo synthesis of protein may be responsible for the observed increase in ribulose-1,5-diphosphate carboxylase activity during greening. However, other factors may be involved with the light-induced stimulation of phosphoribulokinase.