Specificity of diatom Rubisco

Abstract

Rubisco is an inefficient enzyme; this inefficiency is greatest when CO2availability at the site of Rubisco is low. We hypothesise that the selection pressure for a more efficient Rubisco will be greatest in species growing under CO2limited conditions, particularly when low light levels reduce the cost effectiveness of a carbon concentrating mechanism. We determined the specificity factor for four marine diatoms,Thalassiosira antarctica, Skeletonema costatum, Chaetoceros socialis, andThalassiosira hyalinaadapted to the arctic environment.