Isoprene : Dolichols µ¹¸®ÄÝ


2Â÷´ë»ç»ê¹° ¡í Alkaloid, Terpenoid, Phenolic

Isoprene  : Dolichols µ¹¸®ÄÝ

2-C10H16 Mono-terpenes   :  geraniol, limonene and terpineol.
6-C30H48 Tri-terpenes      :  squalene, cholesterol
8-C40H64 Tetra-terpenes   :  lycopene,  carotene

- Mono terpene : ½Ä¹° ³¿¼¼ ¼ººÐÀÇ ´ëºÎºÐ
- °í¼¼±Õ ¼¼Æ÷¸· ¼ººÐ
- ¸ðµç Áö¿ë¼º ºñŸ¹Î : ºñŸ¹Î A, D, E, K
- ½Ä¹°È£¸£¸ó : Áöº£·¼¸°
- Steroid°è È£¸£¸ó

 
 

Dolichols play a role 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 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.[1]

[edit] Role in aging

Dolichol has been suggested to be used as a biomarker for aging.[2] 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.[3]