REVIEW: Inactivation of Organophosphorus Nerve Agents by the Phosphotriesterase from Pseudomonas diminuta

Inactivation of organophosphorus nerve agents by the phosphotriesterase from Pseudomonas diminuta.
Dumas DP, Durst HD, Landis WG, Raushel FM, Wild JR.

Arch Biochem Biophys. 1990 Feb 15;277(1):155-9.

 Let's say that you want to remove a native population, but you do not want to destroy the valuable infrastructure, what do you do? Immediately you should think: chemical weapons! A representation of the potent, chemical weapon sarin is shown below:

 Since these molecules have a fluorine attached (F connected to the P), they degrade very rapidly in water. Given that sarin degrades rapidly in water, it is odd that there exists an enzyme that can degrade this POISONOUS TOXIN!!! So, that is where today's paper comes in, these researchers identified an enzyme that can degrade this compound. To illustrate the fact that this molecule is toxic, you should know that the LD50 is approximately 0.01 mg/kg. Converting that to real numbers, to kill five out of ten Tom Sellecks each Tom Selleck (at 205 lbs) needs to break a single Ritz cracker into 3000 pieces and then eat just one piece.

Enzymes? What are they and what do they do? Enzymes are long strings of molecules with a defined fold that catalyzes some reaction. What molecules is are enzymes composed of? Amino acids, of course. These strings of amino acids fold into many different structures, one of which is shown below.

 The functions catalyzed are amazingly varied and each enzyme is not limited to a single reaction, which comes back to the paper. The enzyme investigated was first identified as a phosphotriesterase, meaning that it can break three bonds on phosphate.  Turns out that it can also break the bonds on sarin and many other herbicides and poisons. Where did they get the enzyme? They took the bacteria Pseudomonas diminuta and isolated the enzyme and then purified it. This enzyme could be have been used to inoculate soldiers in preparation for a chemical attack, but SADLY, USE OF SARIN WAS OUTLAWED IN 1993!!

 This paper is a fine example of typical papers in science: technical and boring. the best papers are from Science or Nature or more prestigious journals because those are the places that entire stories can be told. This is why you will see many papers from Science or Nature here.
 After purifying the enzyme, the researchers added the purified enzyme to some buffer and then added the molecule to be tested. They monitored the progress of the reaction by use of a fluoride electrode which told them the amount of fluoride present over the course of the reaction. They did this for several other molecules, which were also organophosphorus nerve agents.