Effects of Ionic Strength, pH and Milk Serum Composition on Adsorption of Milk Proteins on to Hydroxyapatite Particles

2014 ◽  
Vol 9 (4) ◽  
pp. 341-348 ◽  
Author(s):  
Lucile Tercinier ◽  
Aiqian Ye ◽  
Anne Singh ◽  
Skelte G. Anema ◽  
Harjinder Singh
Keyword(s):  
Ionic Strength ◽  
Milk Proteins ◽  
Milk Serum

Identification of lipid synthesis and secretion proteins in bovine milk

2014 ◽  
Vol 81 (1) ◽  
pp. 65-72 ◽  
Author(s):  
Jing Lu ◽  
Toon van Hooijdonk ◽  
Sjef Boeren ◽  
Jacques Vervoort ◽  
Kasper Hettinga
Keyword(s):  
Dairy Cows ◽  
Milk Fat ◽  
Bovine Milk ◽  
Lipid Synthesis ◽  
Milk Proteins ◽  
Milk Fat Globule Membrane ◽  
Milk Serum ◽  
Milk Fat Globule ◽  
Fat Globule ◽  
Secretion Pathways

Lactation physiology is a process that is only partly understood. Proteomics techniques have shown to be useful to help advance the knowledge on lactation physiology in human and rodent species but have not been used as major tools for dairy cows, except for mastitis. In this paper, advanced non-targeted proteomics techniques (Filter aided sample preparation and NanoLC-Orbitrap-MS/MS) were applied to study the milk fat globule membrane and milk serum fraction, resulting in the identification of 246 proteins. Of these, 23 transporters and enzymes were related to lipid synthesis and secretion in mammary gland and their functions are discussed in detail. The identification of these intracellular transporters and enzymes in milk provides a possibility of using milk itself to study lipid synthesis and secretion pathways. This full-scale scan of milk proteins by using non-targeted proteomic analysis helps to reveal the important proteins involved in lipid synthesis and secretion for further examination in targeted studies.

scholarly journals First Insight into the Variation of the Milk Serum Proteome within and between Individual Cows

Dairy ◽  
2022 ◽  
Vol 3 (1) ◽  
pp. 47-58
Author(s):  
Lina Zhang ◽  
Sjef Boeren ◽  
Jeroen Heck ◽  
Jacques Vervoort ◽  
Peng Zhou ◽  
...  
Keyword(s):  
Protein Identification ◽  
Animal Health ◽  
Milk Proteins ◽  
Serum Proteome ◽  
Milk Serum ◽  
Holstein Friesian ◽  
Dimethyl Labeling ◽  
The Individual ◽  
Related Proteins ◽  
Sample Set

Milk contains all nutrients needed for development of calves. One important group of components responsible for this are the milk proteins. Variation due to feed or animal health, has been studied for the most abundant milk proteins. The aim of this study was to determine the variation between and within cows for their milk serum proteome. Sample Set 1 was collected from Holstein Friesian (HF) cows between November 2011 and March 2012 and prepared using filter aided sample preparation (FASP) followed by LC-MS/MS for protein identification and quantification. The results showed that the milk serum proteome was very constant in mid lactation (four cows at five time points, p > 0.05) between 3 and 6 months in lactation. Sample Set 2 was collected from HF cows in Dec 2012 and analyzed using FASP and dimethyl labeling followed by LC-MS/MS. Significant variation in the milk serum proteome (p < 0.05) between 17 individual cows was found in Sample Set 2. The most variable proteins were immune-related proteins, which may reflect the health status of the individual cow. On the other hand, proteins related to nutrient synthesis and transport were relatively constant, indicating the importance of milk in providing a stable supply of nutrients to the neonate. In conclusion, the milk serum proteome was stable over mid lactation, but differed significantly between individuals, especially in immune-related proteins.

scholarly journals ELECTROPHORETIC SYSTEMS FOR PREPARATIVE FRACTIONATION OF PROTEIN PRECURSORS OF BIOACTIVE PEPTIDES FROM COW’S MILK

2018 ◽  
Vol 12 (2) ◽  
Author(s):  
V. Yukalo ◽  
L. Storozh ◽  
K. Datsyshyn ◽  
O. Krupa
Keyword(s):  
Bioactive Peptides ◽  
Serum Proteins ◽  
Sodium Dodecylsulfate ◽  
Milk Proteins ◽  
Disc Electrophoresis ◽  
Polyacrylamide Gel ◽  
Preparative Electrophoresis ◽  
Milk Serum ◽  
System A ◽  
Gel System

The article considers the possibility of obtaining purified fractions-precursors of bioactive peptides from milk proteins by the method of preparative electrophoresis. To choose an electrophoretic system, a comparative study has been carried out of four methods of electrophoresis in polyacrylamide gel that are used to analyse milk proteins (disc-electrophoresis without disaggregating agents, and disc-electrophoresis in the presence of sodium dodecylsulfate in homogeneous and gradient gel, and electrophoresis in homogeneous gel with urea). Electrophoresis of the total milk protein has shown that none of these systems allows separating effectively all protein precursors of bioactive peptides. The next stage was obtaining two main groups of milk proteins – caseins and serum proteins for electrophoretic fractionation. With the help of analytical electrophoresis, it has been established that each of the obtained groups had a typical proteins composition. Then, the proteins groups obtained were fractionated by preparative electrophoresis using the four electrophoretic systems listed above. In this case, the casein proteins that differ in the primary structure (αS1-, αS2-, β-, and ϰ-caseins) can be effectively separated by preparative electrophoresis on the basis of a homogeneous gel system in the presence of urea. The composition of this electrophoretic system was simplified. Unlike the analytical variant of a homogeneous polyacrylamide gel system, the toxic 2-mercaptoethanol was excluded, and the urea concentration was reduced. For the fractionation of serum proteins, a disc-electrophoresis without disaggregating agents can be used as a basis. It allows obtaining the main precursors of bioactive peptides from milk serum proteins: β-lactoglobulin, α-lactalbumin, serum albumin, and immunoglobulins. The protein precursors obtained by preparative electrophoresis were used to develop the biotechnology of obtaining bioactive phosphopeptides and inhibitors of the angiotensin-converting enzyme.

Binding of zinc to bovine and human milk proteins

1989 ◽  
Vol 56 (2) ◽  
pp. 235-248 ◽  
Author(s):  
Harjinder Singh ◽  
Albert Flynn ◽  
Patrick F. Fox
Keyword(s):  
Ionic Strength ◽  
Binding Sites ◽  
Binding Capacity ◽  
Equilibrium Dialysis ◽  
Whey Proteins ◽  
Milk Proteins ◽  
Association Constants ◽  
Zn Concentration ◽  
Β Lactoglobulin ◽  
Scatchard Plots

SummaryZn binding by whole bovine and human casein and by purified bovine caseins and whey proteins was investigated by equilibrium dialysis. Bovine αs1 casein had the greatest Zn-binding capacity (˜ 11 atoms Zn/mol). Protein aggregation was observed as Zn concentration was increased and- the protein precipitated at a free Zn concentration of 1·7 mM. Zn binding increased with increasing pH in the range 5·4–7·0 and decreased with increasing ionic strength. Competition between Zn and Ca was observed for binding to αs1-casein indicating common binding sites for these two metals. Bovine β-casein bound up to 8 atoms Zn/ mol and precipitated at a free Zn concentration of ˜ 2·5 mM, while K-casein bound 1–2 atoms Zn/mol. Whole bovine and human casein bound 5–8 atoms Zn/mol and precipitated at a free Zn concentration of ˜ 2·0 mM. Scatchard plots for Zn binding to caseins showed upward convexity, possibly due to Zn-induced association of caseins. Apparent average association constants (K¯app) for all caseins were similar (log K¯app 3·0–3·2). Enzymic dephosphorylation of αs1- or whole bovine casein markedly reduced, but did not eliminate, Zn binding. Thus, phosphoserine residues appeared to be the primary Zn-binding sites in caseins. With the exception of bovine serum albumin. which bound over 8 atoms Zn/mol, the bovine whey proteins, β-lactoglobulin, α-lactalbumin and lactotransferrin, had little capacity for Zn binding.

scholarly journals The effect of goat milk fractions on synthesis of milk constituents by rabbit mammary explants and on milk yield in vivo. Evidence for autocrine control of milk secretion

1987 ◽  
Vol 242 (1) ◽  
pp. 285-288 ◽  
Author(s):  
C J Wilde ◽  
D T Calvert ◽  
A Daly ◽  
M Peaker
Keyword(s):  
Culture Medium ◽  
Milk Proteins ◽  
Goat Milk ◽  
Mammary Glands ◽  
Milk Secretion ◽  
Milk Serum ◽  
Autocrine Regulation ◽  
Autocrine Control ◽  
Dose Dependent

Lactose and casein synthesis by rabbit mammary explants in organ culture was inhibited when fractions of goat milk were included in the culture medium. Inhibition was dose-dependent, and readily reversed when milk fractions were removed. The pattern of effects obtained with various fractions of milk indicated that inhibition was caused by a protein of 10,000-30,000 Da, which was present in the milk serum or whey fraction. The inhibitor fraction decreased milk accumulation when injected into lactating rabbit mammary glands via the teat ducts, whereas other milk proteins had no effect. Results are discussed in terms of autocrine regulation of milk synthesis through negative feedback by milk constituents.

scholarly journals The Nutritional Evaluation of Bovine and Human Milk Proteins and the Effects of Supplement of Cystine and Milk Serum Protein to

1975 ◽  
Vol 28 (1) ◽  
pp. 9-16
Author(s):  
Isao NISHIKAWA ◽  
Nobuko MURATA ◽  
Masanobu WARIISHI ◽  
Eiki DEYA ◽  
Gosei KAWANISHI ◽  
...  
Keyword(s):  
Human Milk ◽  
Serum Protein ◽  
Milk Proteins ◽  
Nutritional Evaluation ◽  
Milk Serum

Formation and Structure of Casein Micelles in Lactating Mammary Tissue

1970 ◽  
Vol 28 ◽  
pp. 150-151
Author(s):  
Robert J. Carroll ◽  
Marvin P. Thompson ◽  
Harold M. Farrell
Keyword(s):  
Size Distribution ◽  
G Protein ◽  
Milk Proteins ◽  
Mammary Tissue ◽  
Colloidal System ◽  
Casein Micelles ◽  
The Stability

Milk is an unusually stable colloidal system; the stability of this system is due primarily to the formation of micelles by the major milk proteins, the caseins. Numerous models for the structure of casein micelles have been proposed; these models have been formulated on the basis of in vitro studies. Synthetic casein micelles (i.e., those formed by mixing the purified αsl- and k-caseins with Ca2+ in appropriate ratios) are dissimilar to those from freshly-drawn milks in (i) size distribution, (ii) ratio of Ca/P, and (iii) solvation (g. water/g. protein). Evidently, in vivo organization of the caseins into the micellar form occurs in-a manner which is not identical to the in vitro mode of formation.

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