Inosine 5"-Monophosphate Dehydrogenase 2 (IMPDH2)

IMP dehydrogenase 2 is the rate-limiting enzyme in the de novo guanine nucleotide biosynthesis. It is thus involved in maintaining cellular guanine deoxy- and ribonucleotide pools needed for DNA and RNA synthesis. IMPDH2 catalyzes the NAD-dependent oxidation of inosine-5"""-monophosphate into xanthine-5"""-monophosphate, which is then converted into guanosine-5"""-monophosphate.IMPDH2 shares 84% amino acid identity with IMPDH1. They identified 4 Sp1-binding sites but did not identify a TATA box. The transcriptional start sites were determined by S1 nuclease mapping to be somewhat heterogeneous, but the predominant mRNA species showed a 5-prime end at 102 and 85 nucleotides from the translational initiation codon.