Carboxydismutase activity in plants with and without β-carboxylation photosynthesis.

A comparison was made of the activity of carboxydismutase (ribulose-1,5-diphosphate carboxylase) between higher plant species which possess the β-carboxylation (C4-dicarboxylic acid) pathway for photosynthesis and species which lack this pathway. Contrary to earlier findings no marked difference in the level of this enzyme was found between the two groups of species. Chloroplast-containing vascular-bundle-sheath cells which seem to be present only in plants with β-carboxylation apparently contain relatively high carboxydismutase activity.