| Autor: |
Idrees D; a Center for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia, Jamia Nagar, New Delhi 110025 , India., Shahbaaz M; b Department of Chemistry , Durban University of Technology , Durban 4000 , South Africa., Bisetty K; b Department of Chemistry , Durban University of Technology , Durban 4000 , South Africa., Islam A; a Center for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia, Jamia Nagar, New Delhi 110025 , India., Ahmad F; a Center for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia, Jamia Nagar, New Delhi 110025 , India., Hassan MI; a Center for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia, Jamia Nagar, New Delhi 110025 , India. |
| Abstrakt: |
Mitochondrial carbonic anhydrase VA (CAVA) catalyzes the hydration of carbon dioxide to produce proton and bicarbonate which is primarily expressed in the mitochondrial matrix of liver, and involved in numerous physiological processes including lipogenesis, insulin secretion from pancreatic cells, ureagenesis, gluconeogenesis, and neuronal transmission. To understand the effect of pH on the structure, function, and stability of CAVA, we employed spectroscopic techniques such as circular dichroism, fluorescence, and absorbance measurements in wide range of pH (from pH 2.0 to pH 11.5). CAVA showed an aggregation at acidic pH range from pH 2.0 to pH 5.0. However, it remains stable and maintains its secondary structure in the pH range, pH 7.0-pH 11.5. Furthermore, this enzyme has an appreciable activity at more than pH 7.0 (7.0 < pH ≤ 11.5) with maximum activity at pH 9.0. The maximal values of k cat and k cat /K m at pH 9.0 are 3.7 × 10 6 s -1 and 5.5 × 10 7 M -1 s -1 , respectively. However, this enzyme loses its activity in the acidic pH range. We further performed 20-ns molecular dynamics simulation of CAVA to see the dynamics at different pH values. An excellent agreement was observed between in silico and in vitro studies. This study provides an insight into the activity of CAVA in the pH range of subcellular environment. |
