2'3'-cGAMP-d8 (ammonium salt)

2’3’-cGAMP-d₈ is intended for use as an internal standard for the quantification of 2’3’-cGAMP by GC- or LC-MS. 2’3’-cGAMP is a second messenger produced from ATP and GTP by cGMP-AMP synthase (cGAS) in the cytoplasm of mammalian cells in response to the presence of dsDNA.^1,2,3 It contains a non-canonical 2’5’-phosphodiester bond and binds tightly to the adapter protein stimulator of interferon genes (STING) with a K_d value of 3.79 nM, which is significantly lower than that observed for 2’2’-cGAMP , 3’3’-cGAMP , cyclic di-GMP , and 3’2’-cGAMP (K_ds = 0.287, 1.04, 1.21, and 1.61 µM, respectively).³ It is a potent inducer of IFN-β mRNA expression with an EC₅₀ value of 19.4 nM in L929 cells.³