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Lipoprotein


DATA No : TLP4101 INFORMANT : Kazuo Kondo

NAME : apolipoprotein A-I

COMMON NAME:
SYMBOL: apo A-I
FORMULA: MOL.WT (average) :
BIOLOGICAL ACTIVITY
Function
(1) Apo AI alters a-helix and binds to phospholipids and cholesterol esters to form globules.
(2) Apo AI activates LCAT.
(3) Apo AI acts as an acceptor during transport of free cholesterol between HDL and tissue.(Ref. 4104/4105/4106/4107/4108/4109/4110)
PHYSICAL AND CHEMICAL PROPERTIES
MELTING POINT:Molecular weight:28,016
Isoelectric point:5.4-5.05(Ref. 4101)

BOILING POINT:The number of amino acid residues :243

REFRACTIVE INDEX:Amino acid sequences:In 1975, the primary structure of apo AI was clarified by Baker et al., and the full-length cDNA was cloned by Brewer et al. in 1984.

OPTICAL ROTATION:Structure: The secondary structure of apo AI consists of 11 a-helices (55%),2 b-turns (8%), and 2 b-turns (37%).

DENSITY:Amino acid compositions (Ref. 4113)

SOLUBILITY:Properties:Because Apo AI forms a monomer as well as polymers, such as dimers, tetramers, and octamers in the solution, it is self-associated depending on the protein concentration.(Ref. 4101/4102)
SPECTRAL DATA
UV SPECTRA:

IR SPECTRA:

NMR SPECTRA:

MASS SPECTRA:

OTHER SPECTRA:
CHROMATOGRAM DATA
Method of purification
HDL was initially purified and separated by ultracentrifugation, and the sample containing apo AI was dialyzed against 0.16 M NaCl-1 mM EDTA solution (pH 8.0), then lyophilized. Subsequently, fat was removed from the sample by ether/ethanol (2/3), and the sample was dissolved in 0.01 M Tris-6 M urea solution (pH 8.6) for purification by gel filtration chromatography.
SOURCE
Existing condition and distribution of lipoprotein
In blood, apo AI binds to lipids and exists as a component of chylomicron and HDL.(Ref. 4103)
CHEMICAL SYNTHESIS
Sites of synthesis:The liver and the small intestine.
The rate of synthesis:11mg/kg/day
METABOLISM
Metabolism
Apo AI is synthesized in the liver and samll intestine. Apo AI is initially contained in chylomicron in blood, then produces nascent HDL in combination with phospholipids. Subsequently, nascent HDL is altered to mature HDL by LCAT and taken up in the liver and other organs.
Half life:4.3 days(Ref. 4111)
GENETIC INFORMATION
Genetic information
Gene locus:11;p11-q1
Genearrangement(DNA)(Ref. 4114)(Ref. 4115)
Information of genetic diseases (Tangier disease, familial hypoalphalipoproteinemia, and apo AI deficiency).
Phenotypes:Twenty-two phenotypes represented by apo AI milano has been discovered.(Ref. 4112)
NOTE
Standard range:122 - 161 mg/dl (in human sera)
Diseases and drugs that induce abnormal levels of apo A-I.:Hypoalphalipoproteinemia, LCAT deficiency, and abetalipoproteinemia.
Analytical methods:TIA,ELISA,Nephelometry,SRIDetc.
REFERENCES
[4101]
AUTHOR:Scanu,A.M.(1979) Plasma lipoproteins= an introduction=in The Biochemistry of Atherosclrosis (Scanu,A.M.,Wissler,R.W., and Getz,G.S., eds),Marcel Dekker, New York
TITLE:
JOURNAL:
VOL: PAGE : - ()
[TOP]

[4102]
AUTHOR:Swaney, J. B., and O'Brien, K. J.
TITLE:Cross-linking studies on the state of association of apo A-I and apo A-II from human HDL PubMed ID:183777
JOURNAL:Biochem Biophys Res Commun.
VOL:71 PAGE : 636-643 (1976)
[TOP]

[4103]
AUTHOR:Blue, M. L., Ostapchuk, P., Gordon, J. S., and Williams, D. L.
TITLE:Synthesis of apolipoprotein AI by peripheral tissues of the rooster. A possible mechanism of cellular cholesterol efflux PubMed ID:6809767
JOURNAL:J Biol Chem.
VOL:257 PAGE : 11151-11159 (1982)
[TOP]

[4104]
AUTHOR:Lux, S. E., Hirz, R., Shrager, R. I., and Gotto, A. M.
TITLE:The influence of lipid on the conformation of human plasma high density apolipoproteins PubMed ID:4336379
JOURNAL:J Biol Chem.
VOL:247 PAGE : 2598-2606 (1972)
[TOP]

[4105]
AUTHOR:Fielding, C. J., Shore, V. G., and Fielding, P. E.
TITLE:A protein cofactor of lecithin:cholesterol acyltransferase PubMed ID:4335615
JOURNAL:Biochem Biophys Res Commun.
VOL:46 PAGE : 1493-1498 (1972)
[TOP]

[4106]
AUTHOR:Soutar, A. K., Garner, C. W., Baker, H. N., Sparrow, J. T., Jackson, R. L., Gotto, A. M., and Smith, L. C.
TITLE:Effect of the human plasma apolipoproteins and phosphatidylcholine acyl donor on the activity of lecithin: cholesterol acyltransferase PubMed ID:167813
JOURNAL:Biochemistry.
VOL:14 PAGE : 3057-3064 (1975)
[TOP]

[4107]
AUTHOR:Stein, O., and Stein, Y.
TITLE:The removal of cholesterol from Landschutz ascites cells by high-density apolipoprotein PubMed ID:4128802
JOURNAL:Biochim Biophys Acta.
VOL:326 PAGE : 232-244 (1973)
[TOP]

[4108]
AUTHOR:Jackson, R. L., and Gotto, A. M., Jr.
TITLE:Phospholipids in biology and medicine (first of two parts) PubMed ID:4357163
JOURNAL:N Engl J Med.
VOL:290 PAGE : 24-29 (1974)
[TOP]

[4109]
AUTHOR:Jackson, R. L., Gotto, A. M., Stein, O., and Stein, Y.
TITLE:A comparative study on the removal of cellular lipids from Landschutz ascites cells by human plasma apolipoproteins PubMed ID:170257
JOURNAL:J Biol Chem.
VOL:250 PAGE : 7204-7209 (1975)
[TOP]

[4110]
AUTHOR:Stein, Y., Glangeaud, M. C., Fainaru, M., and Stein, O.
TITLE:The removal of cholesterol from aortic smooth muscle cells in culture and Landschutz ascites cells by fractions of human high-density apolipoprotein PubMed ID:164235
JOURNAL:Biochim Biophys Acta.
VOL:380 PAGE : 106-118 (1975)
[TOP]

[4111]
AUTHOR:Tall, A. R., and Small, D. M.
TITLE:Plasma high-density lipoproteins PubMed ID:213711
JOURNAL:N Engl J Med.
VOL:299 PAGE : 1232-1236 (1978)
[TOP]

[4112]
AUTHOR:Weisgraber, K. H., Rall, S. C., Jr., Bersot, T. P., Mahley, R. W., Franceschini, G., and Sirtori, C. R.
TITLE:Apolipoprotein A-IMilano. Detection of normal A-I in affected subjects and evidence for a cysteine for arginine substitution in the variant A-I PubMed ID:6401735
JOURNAL:J Biol Chem.
VOL:258 PAGE : 2508-2513 (1983)
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[4113]
AUTHOR:Brewer,H.B.Jr., Ronan,R., Meng, M., and Bishop,C. (1986) Isolation and Characterization of Apolipoproteins A-I, A-II, and A-IV, in Methods in ENZYMOLOGY Vol.128 (Segrest J.P., and Albers J.J., eds), pp223-246, Academic Press, Inc.
TITLE:
JOURNAL:
VOL: PAGE : - ()
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[4114]
AUTHOR:Law, S. W., Gray, G., and Brewer, H. B., Jr.
TITLE:cDNA cloning of human apoA-I: amino acid sequence of preproapoA-I PubMed ID:6404278
JOURNAL:Biochem Biophys Res Commun.
VOL:112 PAGE : 257-264 (1983)
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[4115]
AUTHOR:Sharpe, C. R., Sidoli, A., Shelley, C. S., Lucero, M. A., Shoulders, C. C., and Baralle, F. E.
TITLE:Human apolipoproteins AI, AII, CII and CIII. cDNA sequences and mRNA abundance PubMed ID:6328445
JOURNAL:Nucleic Acids Res.
VOL:12 PAGE : 3917-3932 (1984)
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