Abstract
Phosphoribosylpyrophosphate (PRPP) synthetase catalyzes the reaction: Rib-5-P+ATP ⇔ PRPP+AMP. The mammalian enzyme exists as a complex aggregate and a 34 kDa component has been identified as the catalytic subunit. A mutant enzyme in man with hyperactivity leads to elevated purine biosynthesis and eventually to gout. For further study of this enzyme, gene analysis is essential. We screened a cDNA library from rat Yoshida ascites sarcoma cells, using oligonucleotide probes based on the partial amino acid sequences of PRPP synthetase from rat liver. Two distinct clones were obtained and nucleotide sequencing revealed that both clones encode 317 amino acids. The deduced amino acid sequences of the two differ only by 13 residues, whereas the nucleotide sequences are relatively divergent (81 % identity in the coding regions). These results and amino acid sequencing data suggest the presence of two distinct isoforms of the enzyme subunit (PRS I and II, JBC 262:14867, 1987). To analyze the genomic gene structure, a rat genomic EMBL3 library was screened using PRS I and II cDNA probus and 16 clones were obtained, 15 of which were related to PRS I sequence and the other to PRS II. Studies of 7 overlapping PRS I-related clones showed the PRS I structural gene to span about 20 kb. Four other PRS-related clones were quite distinct from the above 7, regarding restriction maps. Thus the presence of additional gene or pseudogene loci for this enzyme is suggested, in analogy to the four loci in humans (HGM 9:739, 1987).
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Tatibana, M., Taira, M., Ishijima, S. et al. 156 ANALYSIS OF MOLECULAR STRUCTURE OF RAT PUOSPHORIBOSYLPYROPHOSPHATE SYNTHETASE GENES. Pediatr Res 24, 137 (1988). https://doi.org/10.1203/00006450-198807000-00180
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DOI: https://doi.org/10.1203/00006450-198807000-00180