 He talks about the extraordinary specificity of action that enzymes display as exemplified by their ability to not only recognize a specific geometric isomer but an optical isomer as well.He points out that enzymes are optically active themselves, L isomers are the "natural" isomers, and that the specificity of action and the sterospecificity of the reaction conducted by an enzyme are the result of the positioning of the molecules with respect to each other.Monod writes that an enzymatic reaction can be seen in two steps