Enzyme co-localization with rubisco in pea leaf chloroplasts.

Immunocytolocalization experiments indicate that carbonic anhydrase, phosphoribulokinase, and P-glycerate kinase are near neighbors of Rubisco in the pea leaf chloroplast stroma. Direct transfer of ribulose bisphosphate and gaseous CO(2) from phosphoribulokinase and carbonic anhydrase to Rubisco, and direct transfer of P-glycerate from Rubisco to P-glycerate kinase in the chloroplast stroma, is then a possibility. Rubisco activase, responsible for the removal of inhibitory sugar phosphates that bind to the active site of Rubisco in the dark, also appears to be co-localized with Rubisco.