Etude comparée de la composition en oses et en amino-acides de la transferrine et de la lactotransferrine humaines

Montreuil, Jean; Spik, Geneviève; Monsigny, Michel; Descamps, Jean-Luc; Biserte, G; Dautrevaux, M

doi:10.1007/bf02297009

Cited by 19 publications

(5 citation statements)

References 22 publications

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“…The glucosamine present in each product could not be accounted for by contamination with glycoproteins for the following reasons: serum proteins were not detected by immunological methods and, although xylose and galactose were found, these sugars are attributable to the atypical sequence of sugars linking chondroitin sulphate chains to the protein core (Gregory et al 1964;Lindahl & Rod6n, 1966;Rod6n & Armand, 1966). Further, even though the conditions used to hydrolyse and isolate neutral sugars were designed to minimize losses (Montreuil et al 1965;Neuberger & Marshall, 1966;Gottschalk, 1966), mannose, glucose or fucose were not detected and only traces ofsialic acid were found. The absence of the last two sugars may imply a species difference, since they have been identified in protein-polysaccharides from bovine cartilage (Gregory et at.…”

Section: Resultsmentioning

confidence: 99%

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Studies on protein–polysaccharides from pig laryngeal cartilage. Extraction and purification

Tsiganos

Muir

1969

Biochemical Journal

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1. Protein-polysaccharides of chondroitin sulphate were extracted from fresh laryngeal cartilage at pH6.8 by two procedures. Procedure I consisted of brief low-speed homogenization in 0.15m (iso-osmotic) sodium acetate and procedure II consisted of longer homogenization followed by prolonged extraction in 10% calcium chloride solution. 2. The protein-polysaccharides in both extracts were isolated and purified by precipitation with 9-aminoacridine hydrochloride. They were free from serum proteins, collagen and nucleic acids and also of degradative enzymes. The absence of such enzymes was shown by viscosity measurements on solutions of protein-polysaccharides incubated for up to 24hr. at pH4 and 6.8. 3. Mannose, glucose or fucose were not detected by paper chromatography and only traces of sialic acid were present. 4. The yield with procedure II was twice that with procedure I and the products differed in their protein and glucosamine contents. 5. Hyaluronic acid was unlikely to have been precipitated at an acid pH, so the glucosamine was attributed to keratan sulphate, as serum proteins were absent. There was no free keratan sulphate in the preparation. 6. Both preparations were heterogeneous in the ultracentrifuge, showing at least three components.

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Section: Resultsmentioning

confidence: 99%

“…of 1 M-HCI at 1000 for 3hr. (Gregory, Laurent & Roden, 1964) and neutralized by treatment with acidic and basic resins (Montreuil, Spik, Dumaisnil & Monsigny, 1965). The hydrolysates were diluted to 0-1M-HCI with water before being applied to a column of Dowex SOW (H+ form) containing 15ml.…”

Section: Methodsmentioning

confidence: 99%

Studies on protein–polysaccharides from pig laryngeal cartilage. Extraction and purification

Tsiganos

Muir

1969

Biochemical Journal

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“…The iron-binding proteins of whey have been studied in the milk of the human, cow, rat, and a marsupial, the quokka (Setonix brachyurus), as well as the rabbit. In the case of humans and cows two distinct proteins are present, one corresponding to serum transferrin, present in very low concentration, and one in higher concentration and with different properties to the serum protein (Schafer, 1951;Johansson, 1960; Montreuil and Mullet, I960; Groves, 1960;Gordon et al, 1962Derechin and Johnson, 1962; Blanc et a!., 1963; Blanc and Isliker, 1964;Montreuil et al, 1965). The latter protein has been called "red protein," "lactotransferrin," or "lactoferrin."…”

Section: Resultsmentioning

confidence: 99%

Isolation and characterization of rabbit serum and milk transferrins. Evidence for difference in sialic acid content only

Baker¹,

Shaw²,

Morgan³

1968

Biochemistry

117

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“…The amino acid composition of human lactoferrin presented in Table 1 [12], whose analyses were based on a single hydrolysis time. I n a previous publication [9], iron-lactoferrin and apolactoferrin were shown to have a considerable absorbance at 280nm ( A i 2~ = 14.6 for the former and 11.2 for the latter).…”

Section: Amino Acid Compositionmentioning

confidence: 99%

Molecular Weight, Single‐Chain Structure and Amino Acid Composition of Human Lactoferrin

Querinjean

Masson

Heremans

1971

European Journal of Biochemistry

183

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A molecular weight of 75000 was computed for human lactoferrin on the basis of a sedimentation coefficient sio,, = 4.93, a partial specific volume Gz0 = 0.715 and a diffusion coefficient Die, = 5.6 x lo-' om2 x sec-l. A molecular weight of 76800 & 1600 was estimated from electrophoreses in agarose acrylamide gel containing sodium dodecylsulphate. No decrease of the molecular weight was observed when the reduced and alkylated or aminoethylated protein was submitted to 6 M urea, indicating that the molecule of lactoferrin consists of a single polypeptide chain. From the analysis of the amino acid composition of human lactoferrin a theoretical molecular weight of 76400 was computed by means of a statistical test. A comparison of the amino acid compositions of human lactoferrin and transferrin suggests that the two proteins are more closely related to one another than was suspected before.Lactoferrin is an iron-binding protein [l-41 occurring in various external secretions [5] as well as in the specific granules of neutrophilic leukocytes [6,7]. It resembles serum transferrin with respect to metal-chelating properties, both proteins being able to bind two atoms of iron. For each Fe3+ taken up,-one molecule of bicarbonate is incorporated [8] and three protons are released [9]. The optical spectra as well as the electron paramagnetic resonance spectra of transferrin and lactoferrin are almost identical [lo].However, the iron-lactoferrin complex is more stable a t low pH than is the iron-transferrin complex [I -41. Lactoferrin Tryptic peptide maps of human lactoferrin [I31 show some 40 spots, which is a much smaller number than would be predicted from the lysine and arginine content. This observation, as well as the presence of two iron-binding sites, suggest the existence of two subunits in lactoferrin. Another argument in favour of this view is the finding by Spik, Monsigny, and Montreuil[l7] of two C-terminal amino acids, as determined by hydrazinolysis. The data described below however do not support this view.All analyses of the amino acid composition of human lactoferrin described in the literature [I 1,121, have been based on single hydrolysis times; furthermore tryptophan content, as reported, is incompatible with the ultraviolet absorbance of this protein [9]. We have analysed the amino acid composition of lactoferrin after 5 hydrolysis times and have determined tryptophan spectrophotometrically. MATERIALS AND METHODS \ Isolation of Lacto ferrinThe purification of lactoferrin was based on a procedure proposed by Johansson [IS], modified in view of increasing the yield.One litre of human milk was precipitated, a t room temperature, by 2 M ammonium sulphate a t pH 7.0.The supernatant was dialysed successively against water and I0 mM sodium phosphate buffer, pH 7.0. To some preparations, after dialysis a t 4 "C, ferrous ammonium sulphate (40mg) was added to the supernatant in order to saturate the lactoferrin with metal. The material was then mixed, a t 4 "C, with 3 g of dry carboxymethyl (CM)-Sephadex (2-50 (P...

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Etude comparée de la composition en oses et en amino-acides de la transferrine et de la lactotransferrine humaines

Cited by 19 publications

References 22 publications

Studies on protein–polysaccharides from pig laryngeal cartilage. Extraction and purification

Studies on protein–polysaccharides from pig laryngeal cartilage. Extraction and purification

Isolation and characterization of rabbit serum and milk transferrins. Evidence for difference in sialic acid content only

Molecular Weight, Single‐Chain Structure and Amino Acid Composition of Human Lactoferrin

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