Molecular analysis of mouse Ampd3 gene encoding heart-type isoform of AMP deaminase

Abstract

Purine metabolism is one mechanism to maintain cellular ATP concentration. The pathway to degrade adenosine nucleotide directly involves in stabilization of the energy charge during ATP consumption. AMP deaminase (E.C.3.5.4.6.; AMPD), which catalyzes the hydrolytic deamination of AMP and converts it to IMP, is thought to play an important role in purine metabolism in all eukaryotic cells. In higher eukaryotes, AMPD has multiple isoforms encoded by a family of AMPD multigenes.1 There are three genes in human: AMPD1, AMPD2, AMPD3, whose products are predominant in muscle (M), liver (L) and erythrocyte (E), respectively.2–4 In rodent, two genes, Ampd1 and Ampd2 that are equivalent to the human AMPD1 and AMPD2, respectively, have been known,2–5 but the gene corresponding to AMPD3 has not been reported. From the analogy of human AMPD, this hypothetical gene has been inferred to code for heart(H)-type AMPD, but molecular studies with rodent heart AMPD has not been done. In this study, mouse cDNA and the gene encoding H-isoform of AMPD have been isolated and characterized for the first time.