Rubisco is a small fraction of total protein in marine phytoplankton

Jenna L. Losh, Jodi N. Young, Francois M. M. Morel

Research output: Contribution to journalArticlepeer-review

100 Scopus citations

Abstract

Ribulose 1,5 bisphosphate carboxylase oxygenase (Rubisco) concentrations were quantified as a proportion of total protein in eight species of microalgae. This enzyme has been assumed to be a major fraction of total protein in phytoplankton, as has been demonstrated in plants, potentially constituting a large sink for cellular nitrogen. Representative microalgae were grown in batch and continuous cultures under nutrient-replete, nitrogen (N)-limited, or phosphorus (P)-limited conditions with varying CO2. Quantitative Western blots were performed using commercially available global antibodies and protein standards. Field incubations with natural populations of organisms from the coast of California were conducted under both nutrient-replete and N-limited conditions with varying CO2. In all experiments, Rubisco represented < 6% of total protein. In nutrient-replete exponentially growing batch cultures, concentrations ranged from 2% to 6%, while in nutrient-limited laboratory and field cultures, concentrations were < 2.5%. Rubisco generally decreased with increasing CO2 and with decreasing growth rates. Based on a calculation of maximum Rubisco activity, these results suggest that phytoplankton contain the minimum concentration of enzyme necessary to support observed growth rates. Unlike in plants, Rubisco does not account for a major fraction of cellular N in phytoplankton. See also the Commentary by Raven

Original languageEnglish (US)
Pages (from-to)52-58
Number of pages7
JournalNew Phytologist
Volume198
Issue number1
DOIs
StatePublished - Apr 2013

All Science Journal Classification (ASJC) codes

  • Physiology
  • Plant Science

Keywords

  • CO
  • Growth rate
  • Nitrogen (N)-limitation
  • Phosphorus (P)-limitation
  • Phytoplankton
  • Rubisco
  • Total protein

Fingerprint

Dive into the research topics of 'Rubisco is a small fraction of total protein in marine phytoplankton'. Together they form a unique fingerprint.

Cite this