Reversible hydration of carbon dioxide. H(+) + hydrogencarbonate = CO2 + H2O When glycosylated and folded, targeted to the chloroplast via a protein-targeting pathway that uses the secretory system via the endoplasmic reticulum (ER) and Golgi apparatus. Strongly expressed in aerial tissues including leaves, stems, flowers and siliques. N-glycosylation is required for activity and chloroplast targeting, probably by facilitating folding and endoplasmic reticulum (ER) export. Disulfide bridge between Cys-52 and Cys-216 is required for correct folding. Belongs to the alpha-class carbonic anhydrase family. Truncated N-terminus.