The monosaccharide composition and sequence of the carbohydrate moiety of human serum low density lipoproteins

Swaminathan, N.; Aladjem, Frederick

doi:10.1021/bi00652a024

Cited by 99 publications

(37 citation statements)

References 43 publications

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“…Firstly, considerable variation is evident in the carbohydrate composition of native LDL, and particularly in neutral and amino sugar content; for example, threefold and twofold differences in mannose and glucosamine respectively are evident between the present results and those of Swaminathan and Aladjem [39]. Overall, there is moderate agreement (Fig.…”

Section: Characterisation Of the T-peptides In Peak IIIsupporting

confidence: 64%

“…Fragments of zones 1 and 2 were largest but amounted to less than a third of the total peptide protein represented by this group. The carbohydrate moieties of the peak 1 and 2 fragments correspond more closely to the sialic acid-containing type-I1 chains (Mr z 2400) characterised by Swaminathan and Aladjem [39], rather than to the mannose-rich type-I units. The deficiency in mannose and elevated content (38 %) of N-acetylglucosamine in the tryptic glycopeptides correlates well with the higher proportion of this monosaccharide in T-LDL.…”

Section: Discussionmentioning

confidence: 77%

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The Surface‐Exposed, Trypsin‐Accessible Segments of Apolipoprotein B in the Low‐Density Lipoprotein of Human Serum

Chapman

Millet

Lagrange

et al. 1982

European Journal of Biochemistry

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Limited tryptic digestion of native low-density lipoprotein (LDL) (e 1.024-1.045 g/ml) liberates some 20 -25 ' %; of its surface-exposed protein as soluble, lipid-free peptides (T-peptides). The T-peptides were resolved into twelve subfractions (peaks 1 -12) by gel filtration chromatography on Bio-Gel P4 in 5 % formic acid, and classified into four major groups on the basis of criteria of size, amino acid composition and predominant C-terminal residue. The first group, peaks 1-4, ( z 30% of total peptide protein; M, 2600-6000), displayed lysine as preponderant C-terminal (Lys : Arg, 3.7 -7.3 : I), were acidic in nature (basic : acidic residues, 0.37 -0.61:1), and more hydrophobic than holo-apo-LDL. Peaks 1 and 2 contained glycopeptides (four or less by fingerprinting), the monosaccharide composition of which resembled that of LDL glycopeptides of type I1 (z 30% of the total; M , , were also apparently derived predominantly by cleavage at lysyl peptidyl bonds (Lys : Arg, 4.6 -4.9 : I), but were distinct in their higher proportion of basic residues (acidic : basic, 0.83-1.05: 1). The third group (peaks 7 and 8) contained peptides approx. eight residues in length, with equal proportions ( z 10%) of arginine and lysine. In contrast, the smaller fragments (2-5 residues) of peaks 9-12 exhibited arginine as major C-terminal residue (Lys:Arg, mean 0.45:1), as well as similar amounts of acidic and basic residues. Examination of the quantitative distribution of lysine and arginine showed 80% of arginines to be present in fragments of eight residues or less, with the majority (45 %) in peptides of 2-5 residues.In contrast, z 70% of total lysines were located in fragments of z 10-20 residues; only z 10% of lysines were in small (2 -5 residue) peptides. Arginine appears therefore to occur most often at short (2-5 residues) and lysine at longer (six or more residues) distances from the next lysine or arginine in trypsin-accessible LDL protein.Clusters of a minimum of two positive charges, often featuring arginine, can thus be envisaged. The resemblance of the amino acid profiles of the major peptide subfractions (peaks 1-8) to that of apolipoprotein B further supports the contention that this apoprotein possesses a repetitive-type sequence. Finally, despite evaluation of peptide heterogeneity by fingerprinting, the inferred presence of incompletely-cleaved tryptic peptides in peaks 3, 4 and 5 precludes attribution of a minimal unique amino acid sequence to apolipoprotein B.For some years, the predominant protein component of the human serum low-density lipoprotein, apolipoprotein B, was regarded strictly as a structural component of this complex macromolecule. More recently, the finding that the specificity of the interaction of LDL with its cellular receptor resides in apo-B [I -31 has spurred investigation into the primary structure of this protein and especially into the structure of that segment(s) which is involved in LDL receptor recognition and binding.At present, we remain ignorant of the exact nature of the site(s) o...

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Section: Characterisation Of the T-peptides In Peak IIIsupporting

confidence: 64%

Section: Discussionmentioning

confidence: 77%

The Surface‐Exposed, Trypsin‐Accessible Segments of Apolipoprotein B in the Low‐Density Lipoprotein of Human Serum

Chapman

Millet

Lagrange

et al. 1982

European Journal of Biochemistry

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“…ApoB is a glycoprotein and contains high mannose N-glycans or biantennary-type oligosaccharides in the case of human low density lipoproteins (26,27). Some investigators show that the glycosylation of proteins and lipids are associated with development, differentiation, and carcinogenesis (28 -30).…”

mentioning

confidence: 99%

The Hepatitis B Virus X Protein Inhibits Secretion of Apolipoprotein B by Enhancing the Expression of N-Acetylglucosaminyltransferase III

Kang

Chung

Lee

et al. 2004

Journal of Biological Chemistry

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“…However since a high proportion of the carbohydrate moiety of LD-lipoprotein is absent from the trypsin-treated particle (30-50 %) [lo, 121, and since trypsinised apo-LD-lipoprotein is highly soluble (in comparison to its native counterpart), these observations suggest to us that monosaccharide sidechains [45] may normally enhance the ability of apolipoprotein-B to aggregate upon delipidation. It is particularly relevant that we have observed the dissociation upon heating of the largest component (bl, mol.…”

Section: Discussionmentioning

confidence: 99%

Limited Tryptic Digestion of Human Serum Low‐Density Lipoprotein: Islation and Characterisation of the‐Deficient Particle and of Its Apoprotien

Chapman

Goldstein

Mills

et al. 1978

European Journal of Biochemistry

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Limited tryptic digestion of human serum low-density (LD) lipoprotein (e 1.024-1.045 g/ml)under defined conditions permitted isolation by gel filtration chromatography of a stable, proteindeficient lipoprotein; the liberated protein was separated as a mixture of peptides of low molecular weight ( < 5000). Comparison of the chemical, physical and immunological characteristics of the trypsin-treated LD-lipoprotein with those of the native preparation revealed several differences, including (a) a diminished protein content (loss of some 20-25% of the total protein of LD-lipoprotein) and increased proportions of the various lipid components, except for triglyceride (probably resulting from a loss of bound free fatty acids with the liberated peptides); (b) a greater heterogeneity in particle size and slightly larger mean diameter; (c) a lower hydrated density and greater peak sf rate than the native LD-lipoprotein (d) an increased net negative charge; and (e) a partial immunological identity between LD-lipoprotein and the corresponding trypsin-treated fraction.While the amino acid compositions of the protein moieties of LD-lipoprotein and of trypsintreated LD-lipoprotein were essentially identical, trypsin-treated apo-LD-lipoprotein was distinct in its complete solubility in urea-containing buffers at high concentrations, and also in its partial solubility in buffers lacking denaturing agents.Comparison of the apoproteins of the native and trypsin-treated LD-lipoproteins by electrophoretic techniques based on molecular weight revealed a transformation of the high-molecular weight material ( > 250 000) characteristic of apo-LD lipoprotein into several polypeptide species (10 major forms) ranging in size from 161 500 to about 10000. The largest of these (band bl : 161 500) could be completely dissociated into smaller components (b2: 93500 and b3: 77000) upon extensive heat treatment at 90 "C. Electrophoresis of the soluble fraction of apo-LD-lipoprotein and of that from its trypsin-treated counterpart in polyacrylamide gels containing urea at basic pH showed the disappearance of the small amounts (< 5 %) of C apoproteins of apo-LDlipoprotein upon tryptic treatment. These results, which were highly reproducible in LD-lipoprotein preparations from different individuals, suggest that trypsin-treated LD-lipoprotein may provide a model for investigation of the organisation and structural role of the principal apoprotein (apolipoprotein-B) in the LD-lipoprotein molecule.The detailed arrangement of the lipid and protein components in the serum low-density lipoprotein Abbreviations. VLD-lipoproteins, very low-density lipoproteins sity as defined; HD-lipoproteins, high-density lipoproteins, e,, 1.063-3.21 g/ml; apo-LD-lipoprotein, the total apoprotein of native LD-lipoprotein; Lp(a), a variant of human serum LD-lipoprotein; TosPheCHzCl, ~-l-(tosylamido-2-phenyl)ethyl chloromethyl ketone. Nomrncluture. Apolipoprotein nomenclature is according to Alaupovic [13].remains the subject of debate [1,2]. Physical, chemical and enzymatic...

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The monosaccharide composition and sequence of the carbohydrate moiety of human serum low density lipoproteins

Cited by 99 publications

References 43 publications

The Surface‐Exposed, Trypsin‐Accessible Segments of Apolipoprotein B in the Low‐Density Lipoprotein of Human Serum

The Surface‐Exposed, Trypsin‐Accessible Segments of Apolipoprotein B in the Low‐Density Lipoprotein of Human Serum

The Hepatitis B Virus X Protein Inhibits Secretion of Apolipoprotein B by Enhancing the Expression of N-Acetylglucosaminyltransferase III

Limited Tryptic Digestion of Human Serum Low‐Density Lipoprotein: Islation and Characterisation of the‐Deficient Particle and of Its Apoprotien

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