Plant Carbonic Anhydrases: II. Preparation and Some Properties of Monocotyledon and Dicotyledon Enzyme Types.

Carbonic anhydrase (EC.4.2.1.1) was purified from leaves of the dicotyledon Pisum sativum L. (56-fold) and from leaves of the monocotyledon Tradescantia albiflora Kunth. (24-fold). The molecular weight of the Pisum enzyme was estimated to be 188,000 +/- 8,000 with subunit sizes of 28,000 +/- 3,000 and 56,600 +/- 3,500. It contained 1 mole zinc per 32,500 +/- 2,000 g protein. The molecular weight of the Tradescantia enzyme was estimated to be 42,000 +/- 2,000 with a subunit size of 27,500 +/- 2,200. It contained 1 mole zinc per 34,000 +/- 2,000 g protein. The two enzyme preparations were different in specific activity, stability in solution, and sensitivity to sulfonamides and inorganic anions. Gel electrophoresis separated each purified preparation into two active enzyme bands.