Effect of heavy metals on the activity of external carbonic anhydrase of microalga Chlamydomonas reinhardtii and microalgae from karst lakes.

摘要

This study investigated the influence of different heavy metals (Cu, Zn, Cd and Pb) on the activity of external carbonic anhydrase [carbonic dehydratase] (CAe) for microalgae collected from two karst lakes located in the central part of the Yunnan-Guizhou Plateau (China) and microalga (Chlamydomonas reinhardtii) in laboratory culture. Algal CAe activity was species-specific and correlated with ambient HCO3-. The effects of Cu, Zn, Cd and Pb on CAe from the same algal species were also different. Cd increased the activity of CAe at low concentrations, and inhibited the activity of CAe with increasing concentrations. The extent of Cu, Zn, Cd and Pb influencing CAe was variable and correlated with the algal species. The effect of heavy metals on CAe appears to be three-fold: (1) competing with CAe cofactor-Zn; (2) indirectly affecting the metabolism of CAe in algal cell; and (3) directly changing bioactivity of CAe.