scholarly journals Microsecond Simulation Analysis of Carbonic Anhydrase – II in Complex with (+)- Cathechin Revealed Molecular Interactions Responsible for Its Amelioration Effect on Fluoride Toxicity

2020 ◽  
Author(s):  
Pulala Raghuveer Yadav ◽  
Hussain Syed ◽  
Sadam DV Satyanarayana ◽  
Pavan Kumar Pindi
Keyword(s):  
Carbonic Anhydrase ◽  
Conformational Changes ◽  
Simulation Analysis ◽  
Carbonic Anhydrase Activity ◽  
Catalytic Site ◽  
Carbonic Anhydrase Ii ◽  
Fluoride Ions ◽  
Skeletal Health ◽  
Ionic Bonds ◽  
Male Wistar Rats

Fluorosis is a chronic condition caused by overexposure to fluoride, marked by impaired dental, skeletal, and non-skeletal health. In presence of excess fluoride ions, in severe cases calcification of the ligaments observed. Earlier studies have suggested that the disruption of carbonic anhydrase activity via ionic homeostasis change was associated with F toxicity. In a recent study, it was demonstrated that Tamarind fruit extract was effective in increasing the urinary F excretion in male Wistar rats via studying the mRNA expression of carbonic anhydrase II (CA II) in kidney homogenates using western blotting, immunohistochemistry and quantitative Realtime PCR based studies. We have carried out this study to understand the detailed molecular level interactions responsible for this tamarind extract based (+)-cathechin compound towards lowering the F toxicity via targeting CA-II. From our study, it was revealed that due to the ability of (+)-cathechin compound to bind tightly filling complete available space at the catalytically important site forming metal coordinated ionic bonds with His94, His96 and His119 residues helps in restricting F ions to interact with Zn ion located at the core of catalytic site responsible for its functionality. On the other hand, interaction of (+)-cathechin compound with Gln92 was observed to be critically important towards inducing conformational changes in CA-II, thus allowing (+)-cathechin compound to burry even deeply inside the catalytic site.

scholarly journals Microsecond Simulation Analysis of Carbonic Anhydrase – II in Complex with (+)- Cathechin Revealed Molecular Interactions Responsible for Its Amelioration Effect on Fluoride Toxicity

2020 ◽  
Author(s):  
Pulala Raghuveer Yadav ◽  
Hussain Syed ◽  
Sadam DV Satyanarayana ◽  
Pavan Kumar Pindi
Keyword(s):  
Carbonic Anhydrase ◽  
Conformational Changes ◽  
Simulation Analysis ◽  
Carbonic Anhydrase Activity ◽  
Catalytic Site ◽  
Carbonic Anhydrase Ii ◽  
Fluoride Ions ◽  
Skeletal Health ◽  
Ionic Bonds ◽  
Male Wistar Rats

Fluorosis is a chronic condition caused by overexposure to fluoride, marked by impaired dental, skeletal, and non-skeletal health. In presence of excess fluoride ions, in severe cases calcification of the ligaments observed. Earlier studies have suggested that the disruption of carbonic anhydrase activity via ionic homeostasis change was associated with F toxicity. In a recent study, it was demonstrated that Tamarind fruit extract was effective in increasing the urinary F excretion in male Wistar rats via studying the mRNA expression of carbonic anhydrase II (CA II) in kidney homogenates using western blotting, immunohistochemistry and quantitative Realtime PCR based studies. We have carried out this study to understand the detailed molecular level interactions responsible for this tamarind extract based (+)-cathechin compound towards lowering the F toxicity via targeting CA-II. From our study, it was revealed that due to the ability of (+)-cathechin compound to bind tightly filling complete available space at the catalytically important site forming metal coordinated ionic bonds with His94, His96 and His119 residues helps in restricting F ions to interact with Zn ion located at the core of catalytic site responsible for its functionality. On the other hand, interaction of (+)-cathechin compound with Gln92 was observed to be critically important towards inducing conformational changes in CA-II, thus allowing (+)-cathechin compound to burry even deeply inside the catalytic site.

scholarly journals Carbonic anhydrase in human platelets

1984 ◽  
Vol 217 (3) ◽  
pp. 727-730 ◽  
Author(s):  
W Siffert ◽  
G Gros
Keyword(s):  
Carbonic Anhydrase ◽  
Carbonic Anhydrase Activity ◽  
Human Platelets ◽  
Carbonic Anhydrase Ii ◽  
Affinity Column ◽  
Kinetic Properties ◽  
Km Value ◽  
Flow Apparatus ◽  
High Concentrations ◽  
Kinetics Of

The carbonic anhydrase activity of human platelets was investigated by measuring the kinetics of CO2 hydration in supernatants of platelet lysates by using a pH stopped-flow apparatus. An average carbonic anhydrase concentration of 2.1 microM was determined for pellets of human platelets. Analysis of the kinetic properties of this carbonic anhydrase yielded a Km value of 1.0 mM, a catalytic-centre activity kcat. of 130000 s-1 and an inhibition constant Ki towards ethoxzolamide of 0.3 nM. From these values, CO2 hydration inside platelets is estimated to be accelerated by a factor of 2500. When platelet lysates were subjected to affinity chromatography, only the high-activity carbonic anhydrase II could be eluted from the affinity column, whereas the carbonic anhydrase isoenzyme I, which is known to occur in high concentrations in human erythrocytes, appeared to be absent.

Carbonic anhydrase activity of intact carbonic anhydrase II-deficient human erythrocytes

1988 ◽  
Vol 65 (4) ◽  
pp. 1472-1480 ◽  
Author(s):  
S. J. Dodgson ◽  
R. E. Forster ◽  
W. S. Sly ◽  
R. E. Tashian
Keyword(s):  
Carbonic Anhydrase ◽  
Normal Subjects ◽  
Relative Difference ◽  
Carbonic Anhydrase Activity ◽  
Carbonic Anhydrase Ii ◽  
Normal Cells ◽  
Reaction Velocity ◽  
Fractional Reduction ◽  
Lower Temperature ◽  
Exchange Technique

Intact erythrocytes from subjects with deficiency of blood carbonic anhydrase (CA) II and from normal subjects were assayed for enzyme activity by use of an 18O exchange technique in a solution containing 25 mM (CO2 + NaHCO3) plus 125 mM NaCl. At 25 degrees C and pH 7.4, the catalyzed reaction velocity was 0.32 +/- 0.04 M/s for the CA II-deficient and 1.60 +/- 0.12 M/s for the normal cells, a ratio of 1:5. Under the same conditions at 37 degrees C the relative difference between the CA II-deficient and normal cells was much less: the velocity for the CA II-deficient cells was 0.84 +/- 0.07 M/s and for the normal cells 1.60 +/- 0.32 M/s, a ratio of 1:1.9. Results were comparable for the hemolysates with the NaHCO3 reduced to 85 mM (the corresponding intracellular concentration): at 25 degrees C CA II-deficient cells had a velocity of 0.36 +/- 0.01 M/s compared with 1.12 +/- 0.04 M/s for the normal cells, a ratio of 1:3.1. At 37 degrees C again the relative difference between hemolysates from CA II normal and deficient cells was much less: the CA II-deficient cells had a reaction velocity of 1.17 +/- 0.22 M/s vs. 2.60 +/- 0.36 M/s for the normal cells, a ratio of 1:2.2. The greater fractional reduction of enzyme velocity of CA II-deficient cells at 25 degrees C compared with 37 degrees C appears to be explained by a greater chloride inhibition of the presumed CA I at the lower temperature.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Deriving C4 photosynthesis parameters by fitting intensive A/Ci curves

2017 ◽  
Author(s):  
Haoran Zhou ◽  
Erol Akçay ◽  
Brent R. Helliker
Keyword(s):  
Carbonic Anhydrase ◽  
Simulation Analysis ◽  
Carbonic Anhydrase Activity ◽  
Sensitivity Analyses ◽  
Estimation Methods ◽  
Photosynthetic Parameters ◽  
Low Leakage ◽  
Fluorescence Measurements ◽  
Photosynthetic Assimilation

ABSTRACTMeasurements of photosynthetic assimilation rate as a function of intercellular CO2 (A/Ci curves) are widely used to estimate photosynthetic parameters for C3 species, yet few parameters have been reported for C4 plants, because of a lack of estimation methods. Here, we extend the framework of widely-used estimation methods for C3 plants to build estimation tools by exclusively fitting intensive A/Ci curves (6-8 more sampling points) for C4 using three versions of photosynthesis models with different assumptions about carbonic anhydrase processes and ATP distribution. We use simulation-analysis, out-of-sample tests, existing in vitro measurements and chlorophyll-fluorescence-measurements to validate the new estimation methods. Of the five/six photosynthetic parameters obtained, sensitivity analyses show that maximal-Rubisco-carboxylation-rate, electron-transport-rate, maximal-PEP-carboxylation-rate and carbonic-anhydrase were robust to variation in the input parameters, while day-respiration and mesophyll-conductance varied. Our method provides a way to estimate carbonic anhydrase activity, a new parameter, from A/Ci curves, yet also shows that models that do not explicitly consider carbonic anhydrase yield approximate results. The two photosynthesis models, differing in whether ATP could freely transport between RuBP and PEP regeneration processes yielded consistent results under high light, but they may diverge under low light intensities. Modeling results show selection for Rubisco of low specificity and high catalytic rate, low leakage of bundle sheath and high PEPC affinity, which may further increase C4 efficiency.

scholarly journals Mechanical loading on the functional activity of carbonic anhydrase II in the periodontium

2020 ◽  
Vol 9 (9) ◽  
pp. e686997719
Author(s):  
Daniela Atili Brandini ◽  
Igor Mariotto Beneti ◽  
Caio Vinícius Lourenço Debortoli ◽  
Marina Fuzette Amaral ◽  
Luiza Monzoli Côvre ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Alveolar Bone ◽  
Carbonic Anhydrase Ii ◽  
Dental Occlusion ◽  
Acid Base ◽  
Chi Square ◽  
Male Wistar Rats ◽  
Chi Square Test ◽  
Quantitative Analyses ◽  
Post Hoc

Carbonic anhydrase II (CA II) is involved with the acid-base homeostasis of tissue. This study aims to evaluate the effect of traumatic dental occlusion (TDO) by means of CA II expression in osteoclasts and osteocytes (near the lamina dura and in the centre of alveolar bone septum), in the periodontal ligament (PDL) and in lining cells (periosteum). For this study, 50 male Wistar rats aged seven weeks were divided into 2 groups: Loaded and Unloaded group. The study periods were 2, 5, 7, 14 and 21 days. The Mann-Whitney U test for quantitative, and the Chi-square test for semi-quantitative analyses were used for group comparison, along with Bonferroni’s post-hoc test. Statistically significant differences between the groups were observed in the number of osteoclasts in the lamina dura (days 5, 7 and 21); the alveolar bone septum (days 2 and 7); osteocytes near the lamina dura (days 2, 5, 7 and 14); and in the centre of the alveolar bone septum (days 2, 5, 7 and 14). There were also differences between-group in CA II expression in the lining cells on days 7 and 14. TDO increases CA II expression in osteoclasts, osteocytes, the PDL and lining cells of the periosteum. Clinical Relevance: Traumatic dental occlusion stimulates higher cells activity of the alveolar bone at short (lamina dura) and long (centre of alveolar bone and periosteum) distances.

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