D-Ribulose 1, 5-diphosphate carboxylase from blue-green algae

D-Ribulose 1, 5-diphosphate carboxylase has been purified to a state of homogeneity from the marine blue-green alga $\text{Agmenellum}$$\text{quadruplicatum}$ strain PR-6. The enzyme has been found to be easily separated from the bulk soluble protein by means of centrifugation into a sucrose gradient. RuDP carboxylase from $\text{Agmenellum}$, upon chromatography using a calibrated Sephadex G-200 column, exhibits a molecular weight of 456,000 daltons, considerably smaller than the protein from eucaryotic algae. Only one polypeptide of approximately 56,000 daltons was obtained upon dissociation in sodium dodecylsulfate.