And these nucleuside triphosphates are basically used to produce to build DNA molecules inside our body. So this reaction is a pretty big deal. Now the question is how do we know that this enzyme is in fact an allosteric enzyme? How do we know that there exists a biological molecule inside our body that is used to basically control the activity of this enzyme? Well, the first evidence that this is an allosteric enzyme came from early studies that basically showed that the rate of formation of this and carbon as pertain depends on the concentration of this final product, the CTP. And this is described in the following graph.