Cloning and characterization of the cDNA encoding human adenylosuccinate synthetase

[摘要]

Adenylosuccinate synthetase (AS) catalyzes the first committed step in the conversion of IMP to AMP. A cDNA was isolated from a human liver library which encodes a protein of 455 amino acids (M _r of 49.925). Alignments of human, mouse, Dictyostelium discoideum and E. coli AS sequences identify a number of invariant residues which are likely to be important for structure and/or catalysis. The human AS sequence was also 19% identical to the human urea cycle enzyme, arginosuccinate synthetase (ASS), which catalyses a chemically similar reaction. Both human liver and HcLa AS mRNA showed signals of 2.3 and 2.8 kb. An unmodified N-terminus is required for function of the human AS enzyme in E. coli mutants lacking the bacterial enzyme. The human cDNA provides a means to assess the possible role of AS abnormalities in unclassified, idiopathic cases of gout.

[学科分类] 生物化学/生物物理

[关键词] Recombinant DNA;De novo purine nucleotide synthesis;Gout;Ade-H;adenylosuccinate lyase gene;AMP;adenosine monophosphate;AS;adenylosuccinate synthetase;ASS;arginosuccinate synthetase;ATP;adenosine triphosphate;bp;base pair;cAMP;cyclic adonosine monophosphate;cGMP;cyclic guanosine monophosphate;CHO;Chinese Hamster Ovary;GDP;guanosine diphosphate;GTP;guanosine monophosphate;IMP;inosine monophosphate;kb;kilobase(s);kDa;kilodalton(s);nt;nucleotide;PCR;polymerase chain reaction;Pi;inorganic phosphate;PPi;pyrophosphate;Pipes;piperazine-N;N′-bis[2-ethane-sulfonic acid]);purA;E. coli gene encoding adenylosuccinate synthetase;SDS;sodium dodecyl sulfate;SSC;sodium chloride;sodium citrate;SSPE;sodium chloride;sodium phosphate containing EDTA