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Endothelial nitric oxide synthase is myristylated
J S Pollock1, V Klinghofer, U Förstermann
1Vascular Biology Group, Abbott Laboratories, Abbott Park, IL 60064.
FEBS Letters
|September 14, 1992
Summary
Endothelial cells attach myristate, not palmitate, to nitric oxide synthase. This fatty acid acylation likely anchors the enzyme to the cell membrane, explaining its particulate nature.
Area of Science:
- Biochemistry
- Cell Biology
- Molecular Biology
Background:
- Endothelium-derived relaxing factor (EDRF) and nitric oxide (NO) are synthesized by an enzyme in the endothelium.
- This enzyme, nitric oxide synthase (NOS), is often described as particulate, unlike other soluble NOS isoforms.
Purpose of the Study:
- To investigate the molecular basis for the particulate nature of endothelial nitric oxide synthase (eNOS).
- To determine if fatty acid incorporation plays a role in anchoring eNOS to the cell membrane.
Main Methods:
- Metabolic labeling of endothelial cells with fatty acids.
- Analysis of fatty acid incorporation into nitric oxide synthase.
Main Results:
- Endothelial cells were found to metabolically incorporate myristate (C14) into nitric oxide synthase.
- Palmitate (C16) was not incorporated into nitric oxide synthase.
- This incorporation suggests fatty acid acylation of the enzyme.
Conclusions:
- The incorporation of myristate into eNOS supports the hypothesis that fatty acid acylation anchors the enzyme to the endothelial cell membrane.
- This acylation mechanism explains why eNOS functions as a particulate enzyme, potentially by direct membrane anchoring or interaction with other membrane proteins.