Some physicochemical properties of carbonic anhydrase in mesembryanthemum crystallinum leaves

Abstract

CA extracted from the leaves of C3 plants as well as CAM mode M.crystallinum plants which had been watering with 0.4 mol NaCl for a week manifested a wide range of the pH optimum. The extractable activity of CA from M. crystallinum was similar to that of C3 and C4 higher plants. Subcellular localization of CA from C3 plants and leaves of the CAM mode M. crystallinum has been investigated using percoll gradient. There were not distinct differences in the subcellular localization of CA activity between C3 and CAM mode plants. We have investigated an influence of 1,10-phenenthroline on the CA activity from M.crystallinum leaves, depending on pH and temperature of the medium. In neutral and weak alkaline medium (pH 7.0–7.4), at temperatures above 30 °C 1,10-phenanthroline completely inactivated the enzyme for 2 h. At the low concentrations DTNB (0.5–1.5 mmol) inhibited 40% of the enzyme activity for 30 min, whereas 3.0–4.0 mmol DTNB at pH 7.8–8.3 eliminated the activity of the enzyme for 60 min. CA was no sensitive to H2O2. Oxidased glutation and sodium-nitroprusside on CA from M. crystallinum leaves did not effect on the enzyme activity.