scholarly journals Isolation and characterization of a major glycoprotein from milk-fat-globule membrane of human breast milk

1981 ◽  
Vol 193 (1) ◽  
pp. 47-54 ◽  
Author(s):  
A Imam ◽  
D J R Laurence ◽  
A M Neville
Keyword(s):  
Breast Milk ◽  
Milk Fat ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Human Breast Milk ◽  
Human Breast ◽  
Milk Fat Globule Membrane ◽  
Isolation And Characterization ◽  
Milk Fat Globule ◽  
Fat Globule

A major periodate–Schiff-positive component from milk-fat-globule membrane of human breast milk has been purified by selectively extracting the membrane glycoproteins, followed by lectin affinity chromatography and gel filtration on Sephadex G-200 in the presence of protein-dissociating agents. The purified glycoprotein, termed epithelial membrane glycoprotein (EMGP-70), has an estimated mol.wt. of 70 000 and yields a single band under reducing conditions on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. The glycoprotein contains 13.5% carbohydrate by weight, with fucose, mannose, galactose, N-acetylglucosamine and sialic acid 17.2, 17.0, 21.1, 7.9 and 36.6% respectively of the carbohydrate moiety. Aspartic and glutamic acid and serine are the major amino acid residues.

Compositional and electrophoretic changes in buffalo milk-fat globule membrane proteins during lactation

1976 ◽  
Vol 43 (3) ◽  
pp. 381-388 ◽  
Author(s):  
Sukhminder Singh ◽  
N. C. Ganguli
Keyword(s):  
Membrane Proteins ◽  
Isoelectric Focusing ◽  
Gel Electrophoresis ◽  
Milk Fat ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Polyacrylamide Gel ◽  
Milk Fat Globule Membrane ◽  
Milk Fat Globule ◽  
Fat Globule

SummaryChemical analyses, polyacrylamide-gel electrophoresis and isoelectric focusing of milk-fat globule membrane proteins (FGMP) obtained from the milk of 2 Murrah buffaloes were done to determine if any change in composition occurred during lactation. Changes in the levels of sialic acid, hexose, hexosamine, N and P were found in the FGMP obtained at different stages of lactation. On the day of parturition, 8 major proteins in FGMP were determined by sodium dodecyl sulphate polyacrylamide-gel electrophoresis whereas 6 major proteins were obtained in FGMP of middle and late lactation milks. Isoelectric focusing of FGMP showed 8–9, 9–13 and 13–16 proteins from colostrum, middle and late lactation milks, respectively and the isoelectric pH of the proteins varied from 5·25 to 7·80, 5·85 to 8·30 and 5·75 to 8·61 respectively.

scholarly journals Inhibitors of Complement Activity in Human Breast-Milk: A Proposed Hypothesis of Their Physiological Significance

1999 ◽  
Vol 8 (2) ◽  
pp. 69-75 ◽  
Author(s):  
Michael Oladipo Ogundele
Keyword(s):  
Breast Milk ◽  
Human Milk ◽  
Complement Activation ◽  
Milk Fat ◽  
Physiological Significance ◽  
Human Breast Milk ◽  
Human Breast ◽  
Complement Activity ◽  
Milk Fat Globule ◽  
Fat Globule

Several natural components abundant in the fluid phase of human breast-milk have been shown to be inhibitors of complement activationin vitro, particularly the classical pathway. These include lysozyme, lactoferrin, lactalbumin alpha and other ligand chelators, complement regulator proteins and other specific soluble inhibitors of complement activation. Their physiological significance probably resides in their ability to restrictin vivocomplement activation to specialized (compartmentalized) sites on the cellular membrane structures in human milk, represented by the abundant surface area of the milk fat globule membranes. This would serve to prevent inflammatory-induced tissue damage of the delicate immature gastrointestinal tract of the newborn as well as the mammary gland itself. A number of recognized and potential inhibitors of complement activity in human milk and other biological fluids are hereby reviewed, with a proposal of their physiological significance.Abbreviations: HBM, human breast-milk; APC, alternative complement activation pathway; MAC, membrane attack complex (C5b-9); MFGM, milk fat globule membrane

scholarly journals Specific antibodies to PAS IV, a glycoprotein of bovine milk-fat-globule membrane, bind to a similar protein in cardiac endothelial cells and epithelial cells of lung bronchioles

1985 ◽  
Vol 228 (1) ◽  
pp. 233-240 ◽  
Author(s):  
D E Greenwalt ◽  
V G Johnson ◽  
I H Mather
Keyword(s):  
Endothelial Cells ◽  
Epithelial Cells ◽  
Milk Fat ◽  
Periodic Acid ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Bovine Milk ◽  
Milk Fat Globule Membrane ◽  
Milk Fat Globule ◽  
Fat Globule

We recently described the tissue distribution of PAS IV (periodic acid/Schiff-positive Band IV), a hydrophobic glycoprotein isolated from bovine milk-fat-globule membrane [Greenwalt & Mather (1985) J. Cell Biol. 100, 397-408]. By using immunofluorescence techniques, PAS IV was detected in mammary epithelial cells, the bronchiolar epithelium of lung, and the capillary endothelium of several tissues, including heart, salivary gland, pancreas, spleen and intestine. In the present paper we describe the specificity of the antibodies used for these studies. Two monoclonal antibodies, E-1 and E-3, were shown by solid-phase immunoassay and immunoaffinity chromatography to be specific for PAS IV (of Mr 76000) in milk-fat-globule membrane and recognize a glycoprotein of slightly higher Mr (85000) in heart. Affinity-purified rabbit antibodies to PAS IV were also shown to recognize components of Mr 76000 and 85000 in fat-globule membrane and heart respectively, by using immunoblotting procedures after sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. Additionally, an immunoreactive protein in lung of Mr 85000 was detected. Despite these differences in molecular size, the fat-globule membrane and heart forms of PAS IV were shown to be very similar by peptide-mapping techniques. The possible significance of the expression of similar forms of PAS IV in both epithelial and capillary endothelial cells is briefly discussed.

Isolation, preparation and the amino acid composition of 4 milk-fat globule membrane proteins solubilized by treatment with sodium dodecyl sulphate

1976 ◽  
Vol 43 (3) ◽  
pp. 401-409 ◽  
Author(s):  
T. E. Cawston ◽  
M. Anderson ◽  
G. C. Cheeseman
Keyword(s):  
Amino Acid ◽  
Membrane Proteins ◽  
Amino Acid Composition ◽  
Acid Composition ◽  
Milk Fat ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Milk Fat Globule Membrane ◽  
Milk Fat Globule ◽  
Fat Globule

SummaryMilk-fat globule membrane (MFGM) proteins were solubilized by treatment with SDS. Four of the major proteins were isolated as SDS complexes using column chromatography. The purity of each isolate was determined by SDS polyacrylamide gel electrophoresis and sufficient of each protein was obtained for amino acid analysis. The amino acid compositions of the isolated MFGM proteins and a total MFGM protein extract were determined. Differences in amino acid composition were found in particular between the major MFGM glycoprotein and the other 3 membrane proteins. The relationships of the amino acid composition to protein properties and structure are discussed.

scholarly journals Isolation and characterization of two individual glycoprotein components from human milk-fat-globule membranes

1982 ◽  
Vol 207 (1) ◽  
pp. 37-41 ◽  
Author(s):  
A Imam ◽  
D J Laurence ◽  
A M Neville
Keyword(s):  
Human Milk ◽  
Milk Fat ◽  
Sodium Dodecyl ◽  
Membrane Glycoproteins ◽  
Lectin Affinity Chromatography ◽  
Isolation And Characterization ◽  
Milk Fat Globule ◽  
Fat Globule ◽  
Milk Fat Globule Membranes ◽  
Human Milk Fat

Two individual glycoprotein components from human milk-fat-globule membranes (MFGM) has been purified by selectively extracting the membrane glycoproteins followed by lectin affinity chromatography and gel filtration on Sephadex G-200 in the presence of protein-disaggregating agents. The purified glycoprotein components, termed ‘epithelial-membrane glycoprotein’ (EMGP-155 and EMGP-39) have estimated molecular weights of 155 000 and 39 000 respectively, and yield a single band under reducing conditions on sodium dodecyl sulphate/polyacrylamide gel. EMGP-155 and EMGP-39 contain 21.0% and 7.0% carbohydrate by weight, with fucose (13.5%, 12.4%), mannose (3.7%, 6.2%), galactose (28.5%, 22.6%), N-acetylglucosamine (17.8%, 7.4%) and sialic acid (36.4%, 51.4%) of the carbohydrate moiety respectively. For both the glycoprotein components, aspartic and glutamic acid and serine are the major amino acid residues.

scholarly journals Comparative Proteomics of Milk Fat Globule Membrane (MFGM) Proteome across Species and Lactation Stages and the Potentials of MFGM Fractions in Infant Formula Preparation

Foods ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1251 ◽  
Author(s):  
Michele Manoni ◽  
Chiara Di Lorenzo ◽  
Matteo Ottoboni ◽  
Marco Tretola ◽  
Luciano Pinotti
Keyword(s):  
Milk Fat ◽  
Human Breast Milk ◽  
Primary Role ◽  
Water Emulsion ◽  
Milk Fat Globule Membrane ◽  
Fat Globules ◽  
Lipid Fractions ◽  
Milk Fat Globules ◽  
Milk Fat Globule ◽  
Fat Globule

Milk is a lipid-in-water emulsion with a primary role in the nutrition of newborns. Milk fat globules (MFGs) are a mixture of proteins and lipids with nutraceutical properties related to the milk fat globule membrane (MFGM), which protects them, thus preventing their coalescence. Human and bovine MFGM proteomes have been extensively characterized in terms of their formation, maturation, and composition. Here, we review the most recent comparative proteomic analyses of MFGM proteome, above all from humans and bovines, but also from other species. The major MFGM proteins are found in all the MFGM proteomes of the different species, although there are variations in protein expression levels and molecular functions across species and lactation stages. Given the similarities between the human and bovine MFGM and the bioactive properties of MFGM components, several attempts have been made to supplement infant formulas (IFs), mainly with polar lipid fractions of bovine MFGM and to a lesser extent with protein fractions. The aim is thus to narrow the gap between human breast milk and cow-based IFs. Despite the few attempts made to date, supplementation with MFGM proteins seems promising as MFGM lipid supplementation. A deeper understanding of MFGM proteomes should lead to better results.

scholarly journals Molecular-weight estimates of milk-fat-globule-membrane protein–sodium dodecyl sulphate complexes by electrophoresis in gradient acrylamide gels

1974 ◽  
Vol 139 (3) ◽  
pp. 653-660 ◽  
Author(s):  
M. Anderson ◽  
T. Cawston ◽  
G. C. Cheeseman
Keyword(s):  
Molecular Weight ◽  
Electrophoretic Mobility ◽  
Sodium Dodecyl Sulphate ◽  
Milk Fat ◽  
Sodium Dodecyl ◽  
Milk Fat Globule Membrane ◽  
Coomassie Blue ◽  
Retardation Coefficient ◽  
Milk Fat Globule ◽  
Fat Globule

The molecular weights of milk-fat-globule-membrane proteins solubilized in sodium dodecyl sulphate were estimated by gradient gel electrophoresis. Standard curves were calibrated from both protein and glycoprotein markers of known molecular weight. Six major proteins were observed with Coomassie Blue staining and six with periodic acid–Schiff staining. The behaviour of the membrane proteins and the marker proteins was compared on several different single strength sodium dodecyl sulphate–polyacrylamide gels between 3 and 12% (w/v). The results were used to calculate the free electrophoretic mobility and retardation coefficient of each protein. Glycoprotein markers had a significantly lower mean free electrophoretic-mobility value than the protein markers. Three of the milk-fat-globule-membrane glycoproteins were shown to be independent of any of the Coomassie Blue-stained bands. On the basis of a comparison of the free electrophoretic-mobility and retardation- coefficient values of markers and unknown proteins the most appropriate standard curve for molecular-weight estimation was chosen.

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