So once again the transition state of this reaction, that's the isomerization of Lproline to deprolene contains an alpha carbon that has planar or trigonal planar, that is trigonal planar. And it turns out that if we use a molecule known as parole two carboxylic acid which basically also contains trigonal planarity on that carbon as seen in the following diagram, then this will be a very, very potent inhibitor and this is in fact a transition state analog for this enzyme. So let's take a look at parole two carboxylic acid and compare the structure to the transition state of this particular reaction. So notice this carbon has trigonal planarity and so does this carbon. So because we have this double bond, that means these three bonds will all lie along the same exact plane. And so these two molecules in fact resemble one another much more than this molecule resembles that substrate.