Carbonic anhydrases from leaves and roots of Daucus carota

Carbonic anhydrases (CAs) (carbonate hydrolase; EC 4.2.1.1) from leaves and roots of mature Daucus carota cv. nantes were purified and characterized. The purification levels were 75- and 73-fold in leaves and roots, respectively. The optimum temperature for the enzymes from both sources was 75 degrees. pH optima were 8.5 and 9.0 in leaves and in roots, respectively. Each enzyme molecule was a hexamer having M(r) 137 800 and the subunit M(r) was 22 800. A dimer CA which has a M(r) of 45 700 was also detected. The amount of this dimer was higher in leaves than in roots. Copyright (C) 1997 Elsevier Science Ltd.