Binding of calcium to casein: Influence of pH and calcium and phosphate concentrations

Zittle, Charles A.; Dellamonica, E. S.; Rudd, Roya; Custer, J.H.

doi:10.1016/0003-9861(58)90159-0

Cited by 52 publications

(19 citation statements)

References 12 publications

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“…The results of this study carried out on whole milk proteins are in the range of the values (6.4-13.2 mg Ca·g −1 protein) obtained by previous authors on whole caseins [3,13,21,29,33] and more particularly on β-caseins [5]. The values of moles Ca bound per 10 5 g proteins (N) vary for each purified protein fraction (Tab.…”

Section: ·Kmentioning

confidence: 78%

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Thermodynamic characterization of calcium-milk protein interaction by isothermal titration calorimetry

Canabady-Rochelle¹,

Sánchez²,

Mellema

et al. 2009

Dairy Sci. Technol.

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-In milk, casein micelles are the natural vectors of calcium (Ca) and constitute an ideal vehicle for the delivery of additional Ca, through Ca-protein interactions. Isothermal titration calorimetry (ITC) is a technique of choice in the study of biomolecular interactions and especially in mineral-protein interactions. Calcium-milk protein interactions were thermodynamically characterized by titration of cow's milk protein with calcium chloride (CC) using ITC. Experiments similar to that of ITC were reproduced and analyzed with other techniques (granulometry and electrophoretic mobility measurement) to better understand the nature of interactions. Binding titration curves were fitted with the "one set of sites model" to determine the thermodynamic parameters (N, 6 mol Ca·mol ). Milk proteins bound up to 8 mg Ca·g −1 of protein at saturation. The global thermodynamic signal obtained upon titration was endothermic. The electrophoretic mobility variations of casein micelles occurring upon CC titration were indicative of Ca-protein interactions of electrostatic nature. Hence, the usual exothermic signal involved in electrostatic interactions was completely hidden by the strong endothermic signal coming from the release of water molecules, either from the hydration shell of the Ca ions and/or dehydration of hydrophobic core of proteins. Particle size variations were indicative of casein micelle retraction upon CC titration.calcium / milk protein / interaction / isothermal titration calorimetry / nano-sizer 摘要 -等温滴定量热法研究钙-乳蛋白质相互作用的热力学性质○ 在乳中，钙与酪蛋白相互作用，使得酪蛋白胶束成为钙的天然载体和理想的传递者○ 等温滴定量热法是用来研究生物分子之间相互作用，特别是矿物元素-蛋白质间相互作用的一种有效方法○ 采用等温滴定量热法用氯化钙滴定乳蛋白质就可以研究钙-乳蛋白相互作用的热力学性质○ 本文同时还采用粒度测定和电泳迁移测定法进行了对比分析○ 根据测定的热力学参数 (N, 6 mol·Ca· mol −1 乳蛋白; 束缚参数 K, 1070 mol·L −1 ; 束缚热焓 H, 1910 cal·mol −1 氯化钙; 熵 S, cal·mol −1 ·K −1 ) 确定的束缚滴定曲线符合 "one set of sited" 模型○ 在饱和状态下每克乳蛋白

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Section: ·Kmentioning

confidence: 78%

“…Indeed, the screen effect of charges by high ionic strength reduces Ca-protein interactions as it can be observed through a partial solubilization of Ca bound to proteins [18]. Furthermore, the effect of pH on the binding of Ca 2+ to milk proteins is also reported in the literature [13,14,29,33].…”

Section: ·Kmentioning

confidence: 96%

Thermodynamic characterization of calcium-milk protein interaction by isothermal titration calorimetry

Canabady-Rochelle¹,

Sánchez²,

Mellema

et al. 2009

Dairy Sci. Technol.

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“…Ca-binding by caseins is pH-dependent (Carr, 1953;Zittle et al 1958;Dickson & Perkins, 1971). A pH increase is generally accompanied by a greater Ca-binding capacity.…”

mentioning

confidence: 94%

Effect of calcium on the hydration of casein. I. Water vapour sorption and fine structure of calcium caseinates compared with sodium caseinates in the pH range 4·6–8·0

Rüegg

Moor

1984

Journal of Dairy Research

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0 3Effect of calcium on the hydration of casein. I. Water vapour sorption and fine structure of calcium caseinates compared with sodium caseinates in the pH range 4-6-80 SUMMARY. Hydration of Ca and Na caseinates which were prepared from whole casein at different pH levels (range 4-7-8-0) was determined by means of water vapour sorption measurements in the water activity (a w ) range O58-O95. Water uptake of Ca caseinates was systematically lower than that of Na caseinates prepared at equal pH, the differences increasing with increasing pH and a w . Plots of the water content v. the amount of added hydroxide at constant a w revealed a linear relationship between water uptake and cation content, suggesting that the increase in water uptake is mainly determined by the amount and type of cations associated with the caseins.In the a w range tested, Ca 2+ adsorbed about 2-7 and Na + 3-18 mol water/mol of cation. This implies that replacement of one mol of casein-bound Na + by Ca 2+ is accompanied by a displacement of 1-11 mol water at a w 0-58-0-95. The loss of water is a consequence of conformational changes induced by the chelating and cross-linking effects of Ca 2+ , which also lead to micelle formation.

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“…Clearly, the effect of adding CaCl 2 at a given pH is similar to that of adding HCl in pure water, which can be explained by the long known fact that Ca 2+ binds specifically to ␤-lg [25]. The net negative charge per proteins can thus be reduced by binding either H + or Ca 2+ .…”

Section: Effect Of Saltmentioning

confidence: 92%

Formation and functionality of self-assembled whey protein microgels

Nicolai

2016

Colloids and Surfaces B: Biointerfaces

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Binding of calcium to casein: Influence of pH and calcium and phosphate concentrations

Cited by 52 publications

References 12 publications

Thermodynamic characterization of calcium-milk protein interaction by isothermal titration calorimetry

Thermodynamic characterization of calcium-milk protein interaction by isothermal titration calorimetry

Effect of calcium on the hydration of casein. I. Water vapour sorption and fine structure of calcium caseinates compared with sodium caseinates in the pH range 4·6–8·0

Formation and functionality of self-assembled whey protein microgels

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