Except in science fiction, all life as we know it today is based on carbon chemistry. Living beings either assimilate the required carbon from already made organic compounds (most heterotrophs) or fix inorganic carbon dioxide to produce the organic compounds (most autotrophs). Carbon dioxide is the end-product of respiration in all domains of life. Plants, algae, and cyanobacteria fix CO2 during photosynthesis while some others do it by using inorganic compounds (lithoautotrophs) (Berg et al. 2010; Berg 2011). In this sense, carbon dioxide is the substrate (for carboxylation) or the product (of decarboxylation) of many enzymatic reactions in biology. A carboxylating enzyme usually links either CO2 or HCO3− with an organic acceptor molecule. Enzymatic carboxylations are physiologically significant routes for CO2 assimilation; CO2 is necessarily reduced in any chemical carbon fixation reaction. Enzymes that fix carbon dioxide either use an external reductant or oxidize the substrate itself. And the reverse of carboxylation is decarboxylation. Carboxylations and decarboxylations are an important class of enzymatic reactions that make and break carbon-carbon bonds. These reactions have assumed special importance in the light of carbon economy and carbon capture (Bierbaumer et al. 2023; Matthews 2023).