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Journal article
The global mass and average rate of rubisco
Proceedings of the National Academy of Sciences - PNAS, Vol.116(10), pp.4738-4743
05/Mar/2019
PMCID: PMC6410859
PMID: 30782794
Abstract
Photosynthetic carbon assimilation enables energy storage in the living world and produces most of the biomass in the biosphere. Rubisco (d-ribulose 1,5-bisphosphate carboxylase/oxygenase) is responsible for the vast majority of global carbon fixation and has been claimed to be the most abundant protein on Earth. Here we provide an updated and rigorous estimate for the total mass of Rubisco on Earth, concluding it is ≈0.7 Gt, more than an order of magnitude higher than previously thought. We find that >90% of Rubisco enzymes are found in the ≈2 × 10 m of leaves of terrestrial plants, and that Rubisco accounts for ≈3% of the total mass of leaves, which we estimate at ≈30 Gt dry weight. We use our estimate for the total mass of Rubisco to derive the effective time-averaged catalytic rate of Rubisco of ≈0.03 s on land and ≈0.6 s in the ocean. Compared with the maximal catalytic rate observed in vitro at 25 °C, the effective rate in the wild is ≈100-fold slower on land and sevenfold slower in the ocean. The lower ambient temperature, and Rubisco not working at night, can explain most of the difference from laboratory conditions in the ocean but not on land, where quantification of many more factors on a global scale is needed. Our analysis helps sharpen the dramatic difference between laboratory and wild environments and between the terrestrial and marine environments.
Details
- Title
- The global mass and average rate of rubisco
- Creators
- Yinon M Bar-On - 972WIS_INST___110Ron Milo - 972WIS_INST___110
- Resource Type
- Journal article
- Publication Details
- Proceedings of the National Academy of Sciences - PNAS, Vol.116(10), pp.4738-4743; 05/Mar/2019
- Number of pages
- 6
- Publisher
- United States
- Language
- English
- DOI
- https://doi.org/10.1073/pnas.1816654116
- PMID
- 30782794
- PMCID
- PMC6410859
- Grant note
- This research was supported by the European Research Council (Project NOVCARBFIX 646827), the Israel Science Foundation (Grant 740/16), the Beck-Canadian Center for Alternative Energy Research, Dana and Yossie Hollander, the Ullmann Family Foundation, the Helmsley Charitable Foundation, the Larson Charitable Foundation, the Wolfson Family Charitable Trust, Charles Rothschild, and Selmo Nussenbaum. R.M. is the Charles and Louise Gartner Professional Chair. Y.M.B.-O is an Azrieli Fellow. We thank Rui Alvez, Peter Crockford, Niv De Malach, Avi Flamholz, Dina Hochhauser, Rob Phillips, John Raven, Mark Stitt, and Xinguang Zhu and two anonymous reviewers for productive feedback on this manuscript. Author contributions: Y.M.B.-O. and R.M. designed research, performed research, analyzed data, and wrote the paper.
- Record Identifier
- 993199719503596
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