<prompt> Azaserine inhibitsGlycinamide ribonucleotide synthetaseGlycinamide ribonucleotide transformylaseFormyl glycinamide ribonucleotide amidotransferaseInosine monophosphate synthase  <response>: In de novo synthesis of purine nucleotides, there are 10 steps.The 4th step addition of N3 is catalysed by the enzyme Formyl glycinamide ribonucleotide amidotransferase.This enzyme is inhibited by azaserine, an anticancer drug. 