Inosinic acid or inosine monophosphate (IMP) is a nucleoside monophosphate. Inosinic acid is important in metabolism. It is the ribonucleotide of hypoxanthine and the first nucleotide formed during the synthesis of purine. It is formed by the deamination of adenosine monophosphate, and is hydrolysed from inosine. IMP is an intermediate ribonucleoside monophosphate in purine metabolism. The enzyme deoxyribonucleoside triphosphate pyrophosphohydrolase, encoded by YJR069C in Saccharomyces cerevisiae and containing (d)ITPase and (d)XTPase activities, hydrolyses ITP releasing pyrophosphate and IMP.