Reverse sphingomyelin‐synthase in rat liver chromatin

FEBS Letters

Magni, Mariapia Viola¹  Lazzarini, Remo¹  Albi, Elisabetta¹ 

[1] Department of Biochemical Sciences and Molecular Biotechnology, Physiopathology, Policlinico Monteluce, 06100 Perugia, Italy

关键词: Chromatin;    Phosphatidylcholine;    Sphingomyelin;    Reverse sphingomyelin-synthase;    SM;    sphingomyelin;    PC;    phosphatidylcholine;    PL;    phospholipid;    DAG;    diacylglycerol;    SM-synthase;    sphingomyelin-synthase;   

DOI  :  10.1016/S0014-5793(03)00810-X

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The chromatin phospholipid fraction is enriched in sphingomyelin content which changes during cell maturation and proliferation. Recently, we have demonstrated that the sphingomyelin variations can be due to chromatin neutral sphingomyelinase and sphingomyelin-synthase activities which differ in pH and K _m optima from those present in nuclear membranes. The sphingomyelin can be used also as a source of phosphorylcholine for phosphatidylcholine synthesis by reverse sphingomyelin-synthase. In the present work we have studied the possible existence of reverse sphingomyelin-synthase activity in nuclear membrane and chromatin. A very low activity was detected in the homogenate, cytosol and nuclear membrane (0.93±0.14, 2.61±0.33 and 0.87±0.13 pmol/mg protein/min, respectively), whereas the activity present in chromatin was 37.09±2.05 pmol/mg protein/min. The reverse sphingomyelin-synthase decreases the intranuclear diacylglycerol pool and increases the intranuclear ceramide pool, whereas sphingomyelin-synthase has an opposite effect. The possible correlation between these enzymes is discussed.

【 授权许可】

Unknown