Xanthosine-5'-triphosphate lithium

Xanthosine-5'-triphosphate (5'-XTP) (10 min) lithium is a potent agonist of phospholipase C in 1321N1 human astrocytoma cells expressing the avian tp2y receptor, with an EC₅₀ of 253 nM^[7].
Xanthosine-5'-triphosphate (10 min) lithium is a potent agonist that inhibits adenylyl cyclase in 1321N1 human astrocytoma cells expressing the avian tp2y receptor, with an EC₅₀ of 172 nM^[7].

Xanthosine-5'-triphosphate (Various concentrations; 30 min) lithium stimulates phosphoinositide phospholipase C in the ampullary epithelium of the posterior vertical semicircular canal of Rana ridibunda with a pK_a of 3.59, an nH of 1.03, and an intrinsic activity of 0.9 relative to 1 mM ATP^[3].
Xanthosine-5'-triphosphate lithium is identified as a substrate of inosine triphosphate pyrophosphatase protein in the 2DE-CETSA dataset of rat hippocampal cytosolic fraction^[5].
Xanthosine-5'-triphosphate(100 µM; 20 min) lithium minimally increases basal adenylyl cyclase activity in Sf9 membranes expressing β₂ARGsαL, but supports agonist-stimulated adenylyl cyclase activity with lower potency than GTP and ITP^[6].
Xanthosine-5'-triphosphate lithium's hydrolysis (20 min) in Sf9 membranes is caused by endogenous nucleotidases, Gsα does not hydrolyze XTP to a measurable extent, and XTP hydrolysis is not regulated by β₂AR ligands^[6].
Xanthosine-5'-triphosphate (139 µM; 20 min) lithium blocks (-)-ISO-stimulated GTP hydrolysis in Sf9 membranes expressing β₂ARGsαL, indicating that XTP binds to Gsα but is not hydrolyzed^[6].