Submitted to: Electrophoresis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/14/2002
Publication Date: 4/1/2003
Citation: Uthus, E.O. 2003. Simultaneous detection of S-adenosylmethionine and S-adenosylhomocysteine in mouse and rat tissues by capillary electrophoresis. Electrophoresis. 24:1221-1226.
Interpretive Summary: S-adenosylmethionine (SAM) is a naturally occurring compound in animal and plant tissues. Its main function is to supply a methyl group (a one carbon compound) to a variety of compounds during their metabolism. Once SAM gives up its methyl group it is converted to S-adenosylhomocysteine (SAH). This compound is important because it is further metabolized to homocysteine (a risk factor for cardiovascular disease). Determination of tissue SAM and SAH has usually been done by high pressure liquid chromatography. This manuscript describes a simple method that uses inherent electrical properties to separate and measure SAM and SAH. SAM and SAH in tissues are extracted with acid. The compounds are then separated in an aqueous buffer solution within a fine glass capillary to which an electrical current has been applied. The method is very sensitive and highly reproducible. Knowing tissue concentrations of SAM and SAH is important for areas of research including work with cancer and cardiovascular disease.
Technical Abstract: 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 um i.d. capillary 60 cm total length, 50 cm to detector window. Samples were separated at 22.5 kV and the separation running buffer was 180mM glycine pH 1.8. The method compares favorably to HPLC methods (r2 = 0.994 for SAM, r2 = 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 nmol SAM/mL and 1-250 nmol SAH/mL. This method can be used to determine tissue concentrations of SAM and SAH, two metabolites than can provide insight into many biological processes.