Chemical Properties
Off-white powder
Uses
Isoxanthopterin is a substrate for the enzyme isoxanthopterin deaminase.
Definition
ChEBI: 2-aminopteridine-4,7-diol is a dihydroxypteridine.
Biological Activity
isoxanthopterin interferes with rna and dna synthesis.isoxanthopterin, a natural intermediate in the pteridine pathway, plays critical roles in pigmentation and cell division.
in vitro
isoxanthopterin was identified as a pteridine of wide natural occurrence and was reported to exerts an inhibitory action on the synthesis of ribosomal rna, possibly soluble rna and on dna in developing eggs of the milkweed bug oncopeltus fasciatus. such effects were measured by partially incubating dechorionated eggs in a solution containing isoxanthopterin and radioactive uridine or thymidine, and then testing the incorporation of the isotope into ribosomal rna or dna. the detailed mechanism of this inhibition had been discussed, and the tentative conclusion was agreed that it was due to an interaction between the pteridine and the nucleic acid (most probably dna) [1].
in vivo
previous animal study showed that rats with inherited retinal dystrophy appeared to differ from healthy rats by an elevated isoxanthopterin excretion in urine. rcs rats responded to feeding of monapterin with an increase of isoxanthopterin excretion. this phenomenon supported the idea that the rcs rat had an increased xanthinoxidase activity compared with healthy rats [2].
Purification Methods
Purify it by repeated precipitation from alkaline solution with acid (preferably AcOH or formic acid), filter, wash well with H2O, then EtOH and dry at 100o. The purity is checked by paper chromatography [RF 0.15 (n-BuOH/AcOH/H2O, 4:1:1); 0.33 (3% aqueous NH4OH). [Goto et al. Arch Biochem Biophys 111 8 1965.] [For biochemistry see Blakley Biochemistry of Folic Acid and Related Pteridines North Holland Publ Co, Amsterdam 1969.] [Beilstein 26 III/IV 3999.]
References
[1] lagowski, j. m. and forrest, h.s. interaction in vitro between isoxanthopterin and dna. proceedings of the national academy of sciences of the united states of america 58(4), 1541-1547 (1967).
[2] g. cremer-bartels, h. gerding, l. hanneken and k. krause. isoxanthopterin excretion of rats with inherited retinal dystrophy. pteridines vol. 2, 1990, pp. 103 -105.
