Sarin nerve gas is an inhibitor of the enzyme acetylcholines

Sarin nerve gas is an inhibitor of the enzyme acetylcholinesterase. Below is occupancy data for different concentrations of free acetylcholine in the presence of 100 nM acetylcholinesterase and [Sarin]free = 50 nM. What type of inhibitor is Sarin and what is the Kd of acetylcholine for acetylcholinesterase?

Solution

Sarin (Nerve Gas) is a organophosphorous compound, it irreversibly inhibit the acetylcholinesterase enzyme. Sarin is a non- competitive inhibitor.

Non- competitive inhibitors reduce the activity of the enzyme by binding not to the active site on the enzyme but to a different site, the ESI (enzyme substrate inhibitor) complex cannot form product and the inhibition cannot be reversed by adding more substrate.

For non cometitive inhibitor Kd can be calculated by:

Vm+I =(Vm-I)/1+(I/Kd)

where I is concentration of inhibitor