Investigation of the Mg-HCO₃⁻-ATPase activity of thyroid tissue cells under various pathologies

Abstract

Distribution of the Mg²⁺-dependent, HCO₃⁻-stimulated ATPase (HCO₃⁻-ATPase) was investigated in sub-cellular fractions of the tissue of the human thyroid gland. It was found that especially high enzymatic activity is characteristic of mitochondria and the endoplasmic reticulum. Correlation between various pathologies of the thyroid and HCO₃⁻-ATPase activity was demonstrated. The activity was evaluated using the difference between active and passive ATPase. During development of the various pathologies, the sub-cellular fractions of the gland showed uneven alterations of HCO₃⁻-ATPase activity. Intriguingly, the enzyme kinetic parameters are also changed, i.e. in the different pathologies both enzyme activity and its affinity towards bicarbonate ions are altered. This raises the question whether pathology is caused by, or results in, changes in the enzyme at the molecular level.

Changes in activity of hippocampus creatine kinase under circadian rhythm disorders

“…We also studied the same parameters under standard ATP concentrations and variable creatine concentrations, 0.07 and 1.0-10.0 mM, respectively. We used the results obtained to measure the kinetic parameters using the Johansen and Lumry equations (Johansen & Lumry 1961;Koshoridze et al 2012):…”