Back to HOME

Lipoprotein


DATA No : TLP4301 INFORMANT : Kazuo Kondo

NAME : apolipoprotein B

COMMON NAME:
SYMBOL: apo B
FORMULA: MOL.WT (average) :
BIOLOGICAL ACTIVITY
Function
(1) Apo B is a structural element of chylomicron, VLDL, IDL, and LDL.(2) Apo B binds to lipids to synthesize chylomicron or VLDL, which is secreted into lymphatic and blood vessels. Apo B accelerates absorption of dietary lipids, especially triglycerides. (3)Apo B binds to cell surface receptors to supply lipids into the cell.(Ref. 4304/4305/4306)
PHYSICAL AND CHEMICAL PROPERTIES
MELTING POINT:Molecular weight: 549,000(Ref. 4301)

BOILING POINT:The number of amino acid residues :

REFRACTIVE INDEX:Amino acid sequences: The primary structure of apo B is repetitive.

OPTICAL ROTATION:Structure: The secondary structure consists of a-helices (25%), b-structures (37%), and disordered structures (37%). However, the secondary structure of apo B varies depending on binding lipids and temperatures.

DENSITY:Amino acid compositions (Ref. 4309/4310/4311)

SOLUBILITY:Properties:Apo B is insoluble in water.(Ref. 4302/4303)
SPECTRAL DATA
UV SPECTRA:

IR SPECTRA:

NMR SPECTRA:

MASS SPECTRA:

OTHER SPECTRA:
CHROMATOGRAM DATA
Method of purification
A fraction containing apo B (1.030 - 1.050 g/ml) was purified by ultracentrifugation, which was defatted by ether/ethanol.
SOURCE
Existing condition and distribution of lipoprotein
In blood, apo B binds to lipids, and is a structural element of LDL and VLDL.
CHEMICAL SYNTHESIS
Sites of synthesis: liver
The rate of synthesis:14.4mg/kg/day
METABOLISM
Metabolism
Apo B is synthesized in the liver and secreted as VLDL. When LPL acts on VLDL, VLDL is converted to LDL, which is incorporated into LDL receptors. In addition, a part of apo B is denatured, and is processed by incorporation into the scavenger receptor pathway.
Half life:2.2days(Ref. 4307)
GENETIC INFORMATION
Genetic information
Gene locus:There are 4 loci for the alpha globulin (Ag) gene on the short arm of chromosome 2.
Gene arrangement (DNA)(Ref. 4309/4310/4311)
:Information of genetic diseases: Ten allotypes (Aga1, c, d, g, h, l, t, x, y, and z) have been discovered.Information of genetic diseases (abetalipoproteinemia, hypobetalipoproteinemia).
Phenotypes:Further investigations are required.(Ref. 4308)
NOTE
Standard range:69-105mg/dl (in human sera)
Diseases and drugs that induce abnormal levels of apo B.
Hyperlipoproteinemia (type IIa, IIb), familial LCAT deficiency, abetalipoproteinemia, and hypobetalipoproteinemia.
Analytical methods:TIA,ELISA,Nephelometry ,SRIDetc.
REFERENCES
[4301]
AUTHOR:Gotto, A. M., Jr., Levy, R. I., Lux, S. E., Birnbaumer, M. E., and Fredrickson, D. S.
TITLE:A comparaive study of the effects of chemical modification on the immunochemical and optical properties of human plasma low-density lipoprotein(s) and apoproteins PubMed ID:4353238
JOURNAL:Biochem J.
VOL:133 PAGE : 369-382 (1973)
[TOP]

[4302]
AUTHOR:Thompson, G. R., Birnbaumer, M. E., Levy, R. I., and Gotto, A. M., Jr.
TITLE:Solid phase radioimmunoassay of apolipoprotein B (apo B) in normal human plasma PubMed ID:182180
JOURNAL:Atherosclerosis.
VOL:24 PAGE : 107-118 (1976)
[TOP]

[4303]
AUTHOR:Kane, J. P., Hardman, D. A., and Paulus, H. E.
TITLE:Heterogeneity of apolipoprotein B: isolation of a new species from human chylomicrons PubMed ID:6930644
JOURNAL:Proc Natl Acad Sci U S A.
VOL:77 PAGE : 2465-2469 (1980)
[TOP]

[4304]
AUTHOR:Alexander, C. A., Hamilton, R. L., and Havel, R. J.
TITLE:Subcellular localization of B apoprotein of plasma lipoproteins in rat liver PubMed ID:177430
JOURNAL:J Cell Biol.
VOL:69 PAGE : 241-263 (1976)
[TOP]

[4305]
AUTHOR:Goldstein, J. L., and Brown, M. S.
TITLE:Binding and degradation of low density lipoproteins by cultured human fibroblasts. Comparison of cells from a normal subject and from a patient with homozygous familial hypercholesterolemia PubMed ID:4368448
JOURNAL:J Biol Chem.
VOL:249 PAGE : 5153-5162 (1974)
[TOP]

[4306]
AUTHOR:Goldstein, J. L., and Brown, M. S.
TITLE:The low-density lipoprotein pathway and its relation to atherosclerosis PubMed ID:197883
JOURNAL:Annu Rev Biochem.
VOL:46 PAGE : 897-930 (1977)
[TOP]

[4307]
AUTHOR:Marsh,J.B.
TITLE:Apoproteins of the lipoproteins in a nonrecirculating perfusate of rat liver. PubMed ID:176290
JOURNAL:J.Lipid Res.
VOL:17 PAGE : 85 -89 (1976)
[TOP]

[4308]
AUTHOR:Malloy, M. J., Kane, J. P., Hardman, D. A., Hamilton, R. L., and Dalal, K. B.
TITLE:Normotriglyceridemic abetalipoproteinemia. absence of the B-100 apolipoprotein PubMed ID:7229035
JOURNAL:J Clin Invest.
VOL:67 PAGE : 1441-1450 (1981)
[TOP]

[4309]
AUTHOR:Knott, T. J., Wallis, S. C., Powell, L. M., Pease, R. J., Lusis, A. J., Blackhart, B., McCarthy, B. J., Mahley, R. W., Levy-Wilson, B., and Scott, J.
TITLE:Complete cDNA and derived protein sequence of human apolipoprotein B-100 PubMed ID:3763409
JOURNAL:Nucleic Acids Res.
VOL:14 PAGE : 7501-7503 (1986)
[TOP]

[4310]
AUTHOR:Chen, S. H., Yang, C. Y., Chen, P. F., Setzer, D., Tanimura, M., Li, W. H., Gotto, A. M., Jr., and Chan, L.
TITLE:The complete cDNA and amino acid sequence of human apolipoprotein B-100 PubMed ID:3759943
JOURNAL:J Biol Chem.
VOL:261 PAGE : 12918-12921 (1986)
[TOP]

[4311]
AUTHOR:Law, S. W., Grant, S. M., Higuchi, K., Hospattankar, A., Lackner, K., Lee, N., and Brewer, H. B., Jr.
TITLE:Human liver apolipoprotein B-100 cDNA: complete nucleic acid and derived amino acid sequence PubMed ID:3464946
JOURNAL:Proc Natl Acad Sci U S A.
VOL:83 PAGE : 8142-8146 (1986)
[TOP]

Last updated June 19, 2007. Copyright © 1989-2007 Japanese Conference on the Biochemistry of Lipids (JCBL). All rights reserved.