Large variation in the Rubisco kinetics of diatoms reveals diversity among their carbon-concentrating mechanisms.

ABSTRACT: While marine phytoplankton rival plants in their contribution to global primary productivity, our understanding of their photosynthesis remains rudimentary. In particular, the kinetic diversity of the CO2-fixing enzyme, Rubisco, in phytoplankton remains unknown. Here we quantify the maximum rates of carboxylation (k cat (c)), oxygenation (k cat (o)), Michaelis constants (K m) for CO2 (K C) and O2 (K O), and specificity for CO2 over O2 (SC/O) for Form I Rubisco from 11 diatom species. Diatom Rubisco shows greater variation in K C (23-68 µM), SC/O (57-116mol mol(-1)), and K O (413-2032 µM) relative to plant and algal Rubisco. The broad range of K C values mostly exceed those of C4 plant Rubisco, suggesting that the strength of the carbon-concentrating mechanism (CCM) in diatoms is more diver

SUBMITTER: Young JN 

PROVIDER: S-EPMC4892730 | biostudies-literature | 2016 May

REPOSITORIES: biostudies-literature