Resumen de Removal of Zinc from Carbonic Anhydrase. A Kinetics Experiment for Upper-Level Chemistry Laboratories
Kathryn R. Williams, Bhavin Adhyaru
The Zn(II) ion in the active site of carbonic anhydrase can be removed by complexation with 2,6-pyridinedicarboxylate (dipicolinate). The kinetics of Zn(II) removal can be followed by two methods. In the standard experiment (suitable for students in biophysical chemistry, biochemistry, or instrumental analysis), aliquots of the reaction mixture are withdrawn at suitable times and tested for the residual enzymatic activity (p-nitrophenyl acetate hydrolysis). In an optional experiment (special project or for students in radiochemistry), the carbonic anhydrase is labeled with 65Zn. Aliquots of the reaction mixture are withdrawn and filtered to separate the liberated 65Zn, which is detected using either a liquid scintillation counter or a gamma counter.
