Acta Pharmacologica Sinica 2008 October; 29 (10): 1227-1232; doi: 10.1111/j.1745-7254.2008.00857.x

Acta Pharmacologica Sinica 2008 October; 29 (10): 1227-1232; doi: 10.1111/j.1745-7254.2008.00857.x

Original Article

Discovery of sphingosine 1-O-methyltransferase in rat kidney and liver homogenates¹

Santosh J SACKET, Dong-soon IM²

Laboratory of Pharmacology, College of Pharmacy (BK21 Project) and Longevity Life Science and Technology Institutes, Pusan National University, Busan 609-735, Korea

Aim: To characterize sphingosine methyltransferase in rat tissues.

Methods: By using S-adenosyl-L-(methyl-³H) methionine, enzymatic activity was measured in the rat liver and kidney homogenates.

Results: The optimum pH and reaction time for the enzyme assay were pH 7.8 and 1 h. ZnCl₂ inhibited the activity, but not MgCl₂, CaCl₂, CoCl₂, or NiCl₂. In the kidney homogenate, enzymatic activity was detectable in the cytosol and all membrane fractions from the plasma membrane and other organelles; however, in the liver homogenate, enzymatic activity was detectable in all membrane fractions, but not in the cytosol. We also tested the enzymatic activity with structurally-modified sphingosine derivatives.

Conclusion: We found sphingosine 1-O-methyltransferase activity in the rat liver and kidney homogenates.

Keywords: sphingosine; O-methylation; methyltransferase; sphingosine kinase; lipid; sphingolipid

¹This work was supported by the Korea Research Foundation Grant funded by the Korean Government (MOEHRD; KRF-20070486000).

²Correspondence to Dr Dong-soon IM.
Phn 82-51-510-2817.
Fax 82-51-513-6754.
E-mail imds@pusan.ac.kr
Received 2008-04-07 Accepted 2008-06-24

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