Xanthine is a purine base and intermediate in the biosynthesis of uric acid (Item No. 16219).{59425,59426} It is formed during mammalian purine catabolism in the liver via oxidation of hypoxanthine (Item No. 22254) by xanthine oxidase (XO), which also oxidizes xanthine to produce uric acid.{59425,59427} Xanthine is also formed from guanine, xanthosine, or hypoxanthine during purine catabolism in plants.{59428} It has been found in a variety of commercial foodstuffs, including beer yeast, mushrooms, vegetables, fish, and beef.{59429} Urinary xanthine levels are decreased in patients with primary gout.{59430} Xanthine has also been used in the synthesis of xanthine derivatives that have anticancer or anti-inflammatory activities in vitro.{59431}
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A purine base and intermediate in uric acid biosynthesis; been found in a variety of commercial foodstuffs; urinary levels are decreased in patients with primary gout; has been used in the synthesis of xanthine derivatives that have anticancer or anti-inflammatory activities in vitro
Formal name: 3,9-dihydro-1H-purine-2,6-dione
Synonyms: 2,6-Dihydroxypurine|NSC 14664
Molecular weight: 152.1
CAS: 69-89-6
Purity: ≥98%
Formulation: A crystalline solid
Cyclin-dependent kinases (CDKs) are key regulators of cell cycle progression and are therefore promising targets for cancer therapy. (R)-Roscovitine is a potent inhibitor of Cdk2/cyclin E with an IC50 value of 0.1 µM.{14988} It also inhibits Cdk7/cyclin H, Cdk5/p35, and cell division cycle (cdc)/cyclin B with IC50 values of 0.49, 0.16, and 0.65 µM, respectively.{14987,14988,14991} (R)-Roscovitine inhibits the growth of rapidly proliferating cells with an average IC50 value of 15.2 µM against a panel of 19 human tumor cell lines.{14988} In murine models of polycystic kidney disease, (R)-roscovitine effectively inhibited disease progression at doses of 50-100 mg/kg.{14564}
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The PtdIn phosphates play an important role in the generation and transduction of intracellular signals.{8344,4096,14518} PtdIns-(3,4,5)-P3-biotin is an affinity probe which allows the PIP3 to be detected through an interaction with the biotin ligand. This design allows PtdIns-(3,4,5)-P3-biotin to serve as a general probe for any protein with a high affinity binding interaction with inositol-(3,4,5)-triphosphate phospholipids, such as phosphatidylinositol 3-kinase, PTEN, or PH-domain-containing proteins.
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The PtdIn phosphates play an important role in the generation and transduction of intracellular signals.{8344,4096,14518} PtdIns-(3,4,5)-P3-biotin is an affinity probe which allows the PIP3 to be detected through an interaction with the biotin ligand. This design allows PtdIns-(3,4,5)-P3-biotin to serve as a general probe for any protein with a high affinity binding interaction with inositol-(3,4,5)-triphosphate phospholipids, such as phosphatidylinositol 3-kinase, PTEN, or PH-domain-containing proteins.
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The tetracycline repressor (TetR) is a transcriptional regulator which normally binds tightly to its palindromic tetO operator DNA, blocking gene expression.{17508} Tet causes the repressor to dissociate from the DNA, allowing transcription to occur. A novel reverse TetR (revTetR) requires tetracycline as a co-repressor to bind tetO and block transcription.{17509,17510} Anhydrotetracycline (hydrochloride) is a powerful effector in both the tetracycline repressor (TetR) and reverse TetR (revTetR) systems, binding the Tet repressor 35-fold more strongly than Tet.{17508,17511} Moreover, anhydrotetracycline poorly binds the 30S ribosomal subunit, compared to Tet,{17512} so it does not act as a general inhibitor of translation and is a poor antibiotic. Perhaps related to this, the concentration of anhydrotetracycline that inhibits eukaryotic cell growth is more than a 1,000-fold above the dose that alters transcription through TetR.{17508}
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