Involved in the de novo synthesis of guanine nucleotides which are not only essential for DNA and RNA synthesis, but also provide GTP, which is involved in a number of cellular processes important for cell division.
J. Biol. Chem. 269, 23830-23837 (1994)[PubMed:8089153]
GMP synthetase is a key enzyme in the de novo synthesis of guanine nucleotides. Human GMP synthetase has been purified to homogeneity, and a cDNA encoding the enzyme has been isolated from the T-lymphoblastoma cell line, A3.01. The open reading frame encodes a protein of 693 amino acids with a predicted molecular weight of 76,725. The cDNA complements a guaA mutant of Escherichia coli, which lacks a functional GMP synthetase and extracts from the transformed E. coli exhibit GMP synthetase activity, which is absent in the parental strain. RNA hybridization analysis shows that human GMP synthetase is encoded by a single 2.4-kilobase message. DNA hybridization analysis suggests that the human GMP synthetase is encoded by one gene. In several human cell lines, the level of mRNA expression is substantially higher in proliferating, transformed cells than in nontransformed cells. In two transformed cell lines, treatment with phorbol ester inhibits proliferation and results in a dramatic down-regulation in the levels of GMP synthetase mRNA and protein.
The chemical reactions and pathways resulting in the formation of purine nucleobases, one of the two classes of nitrogen-containing ring compounds found in DNA and RNA, which include adenine and guanine.
J. Biol. Chem. 269, 23830-23837 (1994)[PubMed:8089153]
GMP synthetase is a key enzyme in the de novo synthesis of guanine nucleotides. Human GMP synthetase has been purified to homogeneity, and a cDNA encoding the enzyme has been isolated from the T-lymphoblastoma cell line, A3.01. The open reading frame encodes a protein of 693 amino acids with a predicted molecular weight of 76,725. The cDNA complements a guaA mutant of Escherichia coli, which lacks a functional GMP synthetase and extracts from the transformed E. coli exhibit GMP synthetase activity, which is absent in the parental strain. RNA hybridization analysis shows that human GMP synthetase is encoded by a single 2.4-kilobase message. DNA hybridization analysis suggests that the human GMP synthetase is encoded by one gene. In several human cell lines, the level of mRNA expression is substantially higher in proliferating, transformed cells than in nontransformed cells. In two transformed cell lines, treatment with phorbol ester inhibits proliferation and results in a dramatic down-regulation in the levels of GMP synthetase mRNA and protein.
Protein involved in the biosynthesis of purine, a nitrogenous heterocyclic base, e.g. adenine, guanine, hypoxanthine and xanthine. De novo synthesis involves a complex, energy-expensive pathway that yields inosine 5'-monophosphate (IMP), a purine ribonucleotide. AMP and GMP are then formed from IMP in separate pathways. Adenine and guanine are found in both DNA and RNA. Hypoxanthine and xanthine are important intermediates in the synthesis and degradation of the purine nucleotides.
Enzyme that catalyzes the joining of two molecules coupled with the breakdown of a pyrophosphate bond in ATP or a similar triphosphate. Sometimes the terms "synthase", "synthetase" or "carboxylase" are also used for this class of enzymes.
A reference proteome is a set of protein sequences derived from a complete proteome which constitutes a defined standard for a particular user community. Reference proteomes are manually defined according to a number of criteria. They cover the proteomes of well- studied model organisms and other proteomes of interest for biomedical and biotechnological research. Reference proteomes have been selected to provide broad coverage of the tree of life, and constitute a representative cross-section of the taxonomic diversity to be found within UniProtKB.
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