Low density lipoprotein biochemistry: Difference between revisions
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==Overview== | ==Overview== | ||
==Biochemisrty== | |||
===Structure=== | |||
* Low-density lipoprotein (LDL) belongs to the [[lipoprotein]] particle family. It has a discoid shape with an average diameter of approximately 20 nm.<ref name="pmid11518754">{{cite journal| author=Segrest JP, Jones MK, De Loof H, Dashti N| title=Structure of apolipoprotein B-100 in low density lipoproteins. | journal=J Lipid Res | year= 2001 | volume= 42 | issue= 9 | pages= 1346-67 | pmid=11518754 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=11518754 }} </ref> However, LDL is considered a heterogeneous molecule due to fluctuating density, size, and flotation rate. | |||
* The average composition of LDL is 20% [[protein]], 20% [[phospholipids]], 40% cholesteryl esters, 10% unesterified [[cholesterol]], and 5% [[triglycerides]].<ref name="pmid11082530">{{cite journal| author=Hevonoja T, Pentikäinen MO, Hyvönen MT, Kovanen PT, Ala-Korpela M| title=Structure of low density lipoprotein (LDL) particles: basis for understanding molecular changes in modified LDL. | journal=Biochim Biophys Acta | year= 2000 | volume= 1488 | issue= 3 | pages= 189-210 | pmid=11082530 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=11082530 }} </ref> | |||
* The LDL particle can be structurally divided into 3 layers according to molecular orientational behavior: | |||
** Outer surface layer with tangential orientation: It forms a shell composed of phospholipid monolayer to cover the core. The phospholipid monolayer is organized in a way that hydrophilic residues with polar head groups interact with the outer aqueous solvent; while the inner hydrophobic residues face the lipid interior. | |||
** Interfacial layer with radial orientation | |||
** Apolar lipid core with random orientation: It contains cholesteryl esters and triglycerides.<ref name="pmid11082530">{{cite journal| author=Hevonoja T, Pentikäinen MO, Hyvönen MT, Kovanen PT, Ala-Korpela M| title=Structure of low density lipoprotein (LDL) particles: basis for understanding molecular changes in modified LDL. | journal=Biochim Biophys Acta | year= 2000 | volume= 1488 | issue= 3 | pages= 189-210 | pmid=11082530 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=11082530 }} </ref><ref name="pmid21131533">{{cite journal| author=Prassl R| title=Human low density lipoprotein: the mystery of core lipid packing. | journal=J Lipid Res | year= 2011 | volume= 52 | issue= 2 | pages= 187-8 | pmid=21131533 | doi=10.1194/jlr.E013417 | pmc=PMC3023539 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=21131533 }} </ref> | |||
* Each native LDL particle contains a single apolipoprotein B-100 (Apo-100) molecule. Apo B-100 is a protein with 4536 [[amino acid]] residues. It encircles the fatty acids keeping them soluble in the aqueous environment.<ref name="pmid11518754">{{cite journal| author=Segrest JP, Jones MK, De Loof H, Dashti N| title=Structure of apolipoprotein B-100 in low density lipoproteins. | journal=J Lipid Res | year= 2001 | volume= 42 | issue= 9 | pages= 1346-67 | pmid=11518754 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=11518754 }} </ref> | |||
* ApoB-100 covers the surface layer of LDL in a heterogeneous fashion, covering one hemisphere of LDL, while keeping other surfaces uncovered with exposed lipids.<ref name="pmid11082530">{{cite journal| author=Hevonoja T, Pentikäinen MO, Hyvönen MT, Kovanen PT, Ala-Korpela M| title=Structure of low density lipoprotein (LDL) particles: basis for understanding molecular changes in modified LDL. | journal=Biochim Biophys Acta | year= 2000 | volume= 1488 | issue= 3 | pages= 189-210 | pmid=11082530 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=11082530 }} </ref> | |||
==References== | ==References== | ||
Revision as of 17:19, 12 September 2013
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Cafer Zorkun, M.D., Ph.D. [2]; Rim Halaby, M.D. [3]
Overview
Biochemisrty
Structure
- Low-density lipoprotein (LDL) belongs to the lipoprotein particle family. It has a discoid shape with an average diameter of approximately 20 nm.[1] However, LDL is considered a heterogeneous molecule due to fluctuating density, size, and flotation rate.
- The average composition of LDL is 20% protein, 20% phospholipids, 40% cholesteryl esters, 10% unesterified cholesterol, and 5% triglycerides.[2]
- The LDL particle can be structurally divided into 3 layers according to molecular orientational behavior:
- Outer surface layer with tangential orientation: It forms a shell composed of phospholipid monolayer to cover the core. The phospholipid monolayer is organized in a way that hydrophilic residues with polar head groups interact with the outer aqueous solvent; while the inner hydrophobic residues face the lipid interior.
- Interfacial layer with radial orientation
- Apolar lipid core with random orientation: It contains cholesteryl esters and triglycerides.[2][3]
- Each native LDL particle contains a single apolipoprotein B-100 (Apo-100) molecule. Apo B-100 is a protein with 4536 amino acid residues. It encircles the fatty acids keeping them soluble in the aqueous environment.[1]
- ApoB-100 covers the surface layer of LDL in a heterogeneous fashion, covering one hemisphere of LDL, while keeping other surfaces uncovered with exposed lipids.[2]
References
- ↑ 1.0 1.1 Segrest JP, Jones MK, De Loof H, Dashti N (2001). "Structure of apolipoprotein B-100 in low density lipoproteins". J Lipid Res. 42 (9): 1346–67. PMID 11518754.
- ↑ 2.0 2.1 2.2 Hevonoja T, Pentikäinen MO, Hyvönen MT, Kovanen PT, Ala-Korpela M (2000). "Structure of low density lipoprotein (LDL) particles: basis for understanding molecular changes in modified LDL". Biochim Biophys Acta. 1488 (3): 189–210. PMID 11082530.
- ↑ Prassl R (2011). "Human low density lipoprotein: the mystery of core lipid packing". J Lipid Res. 52 (2): 187–8. doi:10.1194/jlr.E013417. PMC 3023539. PMID 21131533.