 Using a mixture of adenylate kinase and pyruvate kinase, the deoxyadenosine monophosphate was selectively converted to dATP.After purification, a purity of 90%-95% can be achieved using this method of synthesis with a 40% overall yield.High levels of dATP in the body can be toxic and result in impaired immune function, since dATP acts as a noncompetitive inhibitor for the DNA synthesis enzyme ribonucleotide reductase.