Dolichol
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| Identifiers | |
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| MeSH | Dolichol |
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PubChem CID
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| Properties | |
| C100H164O | |
| Molar mass | 1382.37 |
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Dolichol refers to any of a group of long-chain mostly unsaturated organic compounds that are made up of varying numbers of isoprene units terminating in an α-saturated isoprenoid group, containing an alcohol functional group.
Dolichols play a role in the co-translational modification of proteins known as N-glycosylation in the form of dolichol phosphate. Dolichols function as a membrane anchor for the formation of the oligosaccharide Glc3-Man9-GlcNAc2 (where Glc is glucose, Man is mannose, and GlcNAc is N-acetylglucosamine). This oligosaccharide is transferred from the dolichol donor onto certain asparagine residues (onto a specific sequence that is "Asn-X-Ser/Thr") of newly forming polypeptide chains. Dolichol is also involved in transfer of the monosaccharides to the forming Glc3-Man9-GlcNAc2-Dolichol carrier.
In addition, dolichols can be adducted to proteins as a posttranslational modification, a process in which branched carbohydrate trees are formed on a dolichol moiety and then transferred to an assembly of proteins to form a large glycoprotein in the rough endoplasmic reticulum.
Dolichols are the major lipid component (14% by mass) of human substantia nigra (SN) neuromelanin. Dolichol phosphate was discovered at the University of Liverpool in the 1960s, although researchers did not know its function at the time of discovery.
Dolichol has been suggested to be used as a biomarker for aging. During aging, the human brain shows a progressive increase in levels of dolichol, a reduction in levels of ubiquinone, but relatively unchanged concentrations of cholesterol and dolichyl phosphate. In the neurodegenerative disease Alzheimer's disease, the situation is reversed, with decreased levels of dolichol and increased levels of ubiquinone. The concentrations of dolichyl phosphate are also increased, while cholesterol remains unchanged. This study [1] shows that the isoprenoid changes in Alzheimer's disease differ from those occurring during normal aging, and, therefore, this disease cannot be regarded as a result of premature aging. The increase in the sugar carrier dolichyl phosphate may reflect an increased rate of glycosylation in the diseased brain, and the increase in the endogenous anti-oxidant ubiquinone an attempt to protect the brain from oxidative stress, for instance, induced by lipid peroxidation.
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