Binding of QNB and Atropine to Muscarinic Acetylcholine Essay Assignment paper
Binding of QNB and Atropine to Muscarinic Acetylcholine RESULT AND DISCUSSION
Here in the graph the values are plotted for QNB bound with atropine (with as show in the graph), QNB bound without atropine (Without as shown in the graph) and Corrected vales are obtained by subtracting QNB bound with atropine from the QNB bound without atropine (corrected as shown in the graph ) against time. Here QNB bound without atropine is total amount of QNB bound to the receptor; QNB bound with atropine is the Non-specific binding of QNB to the receptor and corrected is the specific binding of QNB to the receptor. Binding of QNB and Atropine to Muscarinic Acetylcholine Essay Assignment paper
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After a particular time of incubation receptors reach equilibrium, where no more binding of QNB takes place to the binding sites. At this point when no more binding of QNB takes place the plateau is formed in the graph showing saturation. This incubation time is approximately “45 min” as shown by the graph reaching the plateau.
The graph shows us that with and corrected points of the graph forms a plateau after reaching incubation time of approximately 45 min. If an addition incubation time was taken after 60 min we would have got a plateau for without graph also showing us a plateau. Binding of QNB and Atropine to Muscarinic Acetylcholine Essay Assignment paper
The graph shows that the cmp value increase over time after which when reaching a particular time no more binding occurs thus forming a plateau showing the saturation or equilibrium has reached. Small decline in the graph can be seen at time 30 to 45 min, this could have been due to experimental errors. The errors could have been caused during pipetting, in proper vacuum, formation of bubbles, adding samples properly between time intervals etc. This can be avoided by more careful handling of the instrument and doing a initial check up for errors so as to not cause changes in the experiment’s result. Binding of QNB and Atropine to Muscarinic Acetylcholine Essay Assignment paper
Taking the above data into consideration we have chosen 45 min as incubation time for determining IC50 of atropine. This is because, saturation of binding sites is achieved and no further unbinding of QNB also occurs, as the ‘off-rate’ or reaction constant of QNB unbinding is very low. So there is no further change in the amount of bound QNB and hence this incubation time is considered appropriate.
By serial dilution different concentration of atropine was prepared. The graph shows us that the amount to QNB bound to the receptor of the membrane reduces with increase in concentration. This happens because atropine is a competitive binder and binds competitively with specific sites to the receptor. The amount of QNB specifically bound will be inversely proportional with atropine concentration. Binding of QNB and Atropine to Muscarinic Acetylcholine Essay Assignment paper
Half maximal inhibitory concentration (IC50) is a measure of how effective a compound is in inhibiting biological or biochemical function. This is a quantitative measure that let us know how much concentration of the drug or biological substance (inhibitor) is required to inhibit a given biological process by half. So we are calculating the IC50 of atropine to determine its potency. It is calculated by taking atropine concentration at which 50% QNB is displaced. The IC 50 value was found to be 0.0008912 μM. This shows that atropine is a drug with good potency. Ic 50 does not directly discuss the binding constant so we cannot compare the binding affinity of QNB and receptor. Binding of QNB and Atropine to Muscarinic Acetylcholine Essay Assignment paper