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Phosphatidylethanolamine N-methyltransferase from liver
1Department of Biochemistry, University of Alberta, Edmonton, Canada.
Biochimica Et Biophysica Acta
|November 25, 1997
Summary
Phosphatidylethanolamine N-methyltransferase (PEMT) is crucial for phosphatidylcholine synthesis. PEMT gene deletion eliminates this activity, indicating its vital role in liver function and potentially hepatocyte growth.
Area of Science:
- Biochemistry
- Molecular Biology
- Cell Biology
Background:
- Phosphatidylethanolamine N-methyltransferase (PEMT) catalyzes the conversion of phosphatidylethanolamine to phosphatidylcholine.
- Two forms, PEMT1 (endoplasmic reticulum) and PEMT2 (mitochondria-associated membrane), exist.
- The PEMT gene encodes both enzyme forms.
Purpose of the Study:
- To characterize the PEMT gene and its encoded enzymes.
- To investigate the regulation of PEMT activity and gene expression.
- To explore the role of PEMT in hepatocyte growth and cell division.
Main Methods:
- Gene cloning and characterization of rat liver PEMT2 cDNA and murine PEMT gene.
- Enzyme activity assays following PEMT gene deletion.
- Analysis of substrate and product regulation.
- Investigation of gene expression regulation during development and dietary choline supply.
Main Results:
- The PEMT gene encodes both PEMT1 and PEMT2.
- Deletion of the PEMT gene abolished phosphatidylethanolamine to phosphatidylcholine conversion in liver.
- PEMT activity is regulated by substrate availability (phosphatidylethanolamine, S-adenosylmethionine) and product inhibition (S-adenosylhomocysteine).
- PEMT gene expression is modulated by development and dietary choline.
Conclusions:
- The PEMT gene is essential for phosphatidylcholine biosynthesis via the methylation pathway in the liver.
- PEMT activity and expression are subject to complex regulatory mechanisms.
- Evidence suggests PEMT plays a role in regulating hepatocyte growth and cell division.