So in this reaction we have two substrate molecules, the ATP as well as the MMP. Now what do we have to know about nucleotide monophosphate kinases? Well, there are three things that you have to keep in mind about these enzymes and let's begin by discussing the first one. So NMP kinase molecules, for example adenylate kinase or guanylate kinase. So guanylate kinase basically catalyzes the transfer of the phosphoryl group from GTP onto some type of NMP. So if we study the three dimensional structure of all these different types of NMP kinases, for example, these two, we're going to see a region that is conserved.