Simultaneous detection of S-adenosylmethionine and S-adenosylhomocysteine in mouse and rat tissues by capillary electrophoresis.

A capillary electrophoresis method for the determination of S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH) in rat liver and kidney and mouse liver is described. The method can also be used to determine SAM in whole blood. The method provides rapid (approximately 16 min sample to sample) resolution of both compounds in perchloric extracts of tissues. Separation was performed by using an uncoated 50 microm ID capillary with 60 cm total length (50 cm to the detector window). Samples were separated at 22.5 kV and the separation running buffer was 200 mM glycine pH 1.8 (with HCl). The method compares favorably to HPLC methods (r (2) = 0.994 for SAM, r (2) = 0.998 for SAH) and has a mass detection limit of about 10 fmol for both SAM and SAH at a signal-to-noise ratio of 3. The method is linear over ranges of 1-100 microM SAM and 1-250 microM SAH. This method can be used to determine tissue concentrations of SAM and SAH, two metabolites that can provide insight into many biological processes.