R ubisco: still the most abundant protein of Earth?

作者：John Albert Raven · 发表于：New Phytologist · 年份：2013 · DOI：10.1111/nph.12197 · 被引用次数：179 · 研究领域：Photosynthetic Processes and Mechanisms、Plant responses to elevated CO2、Marine and coastal ecosystems

'How can leaf Rubisco N values for vascular plants best be compared with whole organism (whole cell) Rubisco protein values for cyanobacteria and algae?' Ellis (1979) suggested that Rubisco was the most globally abundant protein in land biota, based on the enzyme from C3 land plants. However, work on organisms with Rubiscos with different kinetics and CO2 supply mechanisms, specifically CO2 concentrating mechanisms (CCMs), suggests that less Rubisco is needed in some organisms to catalyse a given rate of CO2 assimilation. In this issue of New Phytologist, Losh et al. provide a very important data set which measures the Rubisco content in cultures of eight species of microalgae, and also in natural populations of marine phytoplankton. A very important finding is that the protein content of the algal cells, as a fraction of total cell protein, is only about a fifth of that in the leaves of C3 plants, and is the minimum Rubisco content needed to support the observed maximum growth rate of the algae. The highest values of Rubisco per unit nitrogen (N) among the flowering plants (Table 1) are found in C3 plants relying on diffusive entry of CO2 to Rubisco from the bulk atmosphere. All the other organisms listed have CCMs; for the terrestrial vascular plants these are all C4 plants, and they have lower Rubisco values on a leaf blade N basis (Table 1), based on the measurements on seven NADme (using NAD malic enzyme as the C4 decarboxylase) grasses, as well as for seven NADPme (usin...