Modulation of deoxycytidine kinase substrate specificity in lymphocyte

Adenylosuccinate lyase catalyzes two similar reactions in the de novo purine biosynthetic pathway; the cleavage of succinylaminoimidazole carboxamide ribotide to aminoimidazole carboxamide ribotide and fumarate and the cleavage of adenylosuccinate to adenylate and fumarate. Adenylosuccinate lyase is also a participant in the purine nucleotide cycle which plays an important role in maintaining the AMP levels in muscle. In order to understand the structure/function and evolutionary relationships of the members of the fumarate gene family and to evaluate the possible existence of tissue specific isoforms of adenylosuccinate lyase, we have isolated and characterized the murine cDNA and gene encoding adenylosuccinate lyase. The cDNA has 94% and 87% identity to the human sequence at the amino acid and nucleotide levels respectively. The gene is about 27 kb and contains 13 exons. Comparison of the exon/intron structure of this gene with the argininosuccinate lyase gene did not suggest gene duplication or exon shuffling as a mechanism of evolution in the fumarate gene family.