Kinetics ofAccumulation ofRibulose-1,5-bis phosphate

Thepreparation ofa rabbit antibody toribulose-1,5-bisphosphate carboxylase (RuBPCase) fromEugkna gracilis andits usetoquantitate RuBPCase indark- andlight-grown cells andduring light-induced chloroplast development (greening) aredescribed. Light-grown Euglena have atleast 36times moreRuBPCase thandark-grown Eugkna. Light is required forboth theinitiation andcontinued increase innetsynthesis of RuBPCase overthedarklevel: brief illumination 12hours before exposuretocontinuous light eliminates thelags intheaccumulation and increase inactivity ofRuBPCase (as well asinchlorophyll accumulation) netsynthesis isblocked ingreening cells returned tothedark orexposed to3-3,4-dichlorophenyl)-1,1-dimethylurea. Streptomycin orcycloheximideprevents RuBPCase accumulation whenadded atthebeginning of greening butonlypartially blocks accumulation whenaddedafter 25 hours ofgreening. After 24hours ofgreening, theacitivity ofRuBPCase permilligram chlorophyll continues toincrease slowly while concentration oftheenzyme permilligram chlorophyll remains constant. This increased activity maybeduetoactivation oftheenzyme aswell asto netsynthesis.