Hostname: page-component-7479d7b7d-wxhwt Total loading time: 0 Render date: 2024-07-09T05:46:22.107Z Has data issue: false hasContentIssue false
  • English
  • Français

Binding of zinc to bovine and human milk proteins

Published online by Cambridge University Press:  01 June 2009

Harjinder Singh ,
Albert Flynn  and
Patrick F. Fox
Harjinder Singh
Affiliation:
Departments of Food Chemistry, University College, Cork, Irish Republic
Albert Flynn
Affiliation:
Nutrition, University College, Cork, Irish Republic
Patrick F. Fox
Affiliation:
Departments of Food Chemistry, University College, Cork, Irish Republic
Get access Rights & Permissions [Opens in a new window]

Summary

Zn 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.

Type
Original Articles
Information
Journal of Dairy Research , Volume 56 , Issue 2 , May 1989 , pp. 235 - 248
Copyright
Copyright © Proprietors of Journal of Dairy Research 1989

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Allen, R. J. L. 1940 The estimation of phosphorus. Biochemical Journal 34 858–865CrossRefGoogle ScholarPubMed
Anon. 1986 Zinc bioavailability of human and cow's milk. Nutrition Reviews 44 181–183Google Scholar
Andrews, A. T. 1983 Proteinases in normal bovine milk and their action on caseins. Journal of Dairy Research 50 45–55CrossRefGoogle ScholarPubMed
Association Of Official Agricultural Chemists 1960 Official Methods of Analysis of the AOAC, 9th edn (Ed. Horwitz, W.). Washington, DC: AOACGoogle Scholar
Blakeborough, P., Gurr, M. I. & Salter, D. N. 1986 Digestion of the zinc in human milk, cow's milk and a commercial babyfood: some implications for human infant nutrition. British Journal of Nutrition 55 209–217CrossRefGoogle Scholar
Blakeborough, P., Salter, D. N. & Gurr, M. I. 1983 Zinc binding in cow's milk and human milk. Biochemical Journal 209 505–512CrossRefGoogle ScholarPubMed
Casey, C. E., Walravens, P. A. & Hambidge, K. M. 1981 Availability of zinc: loading tests with human milk, cow's milk and infant formulas. Pediatrics 68 394–396CrossRefGoogle ScholarPubMed
Dahlquist, F. W. 1978 The meaning of Scatchard and Hill plots. Methods in Enzymology 48 270–299CrossRefGoogle ScholarPubMed
Dalgleish, D. G. & Parker, T. G. 1980 Binding of calcium ions to bovine αs1-casein and precipitability of the protein–calcium ion complexes. Journal of Dairy Research 47 113–122CrossRefGoogle Scholar
Dickson, I. R. & Perkins, D. J. 1971 Studies on the interactions between purified bovine caseins and alkaline- earth-metal ions. Biochemical Journal 124 235–240CrossRefGoogle ScholarPubMed
Evans, G. W. & Johnson, P. E. 1977 Determination of zinc availability in foods by the extrinsie label technique. American Journal of Clinical Nutrition 30 873–878CrossRefGoogle ScholarPubMed
Flynn, A. & Power, P. 1985 Nutritional aspects of minerais in bovine and human milks, In Developments in Dairy Chemistry-3. Lactose and minor constituents pp. 183–215 (Ed. Fox, P. F.). London: Elsevier Applied Science PublishersGoogle Scholar
Fox, P. F. & Guiney, J. 1972 A procedure for the partial fractionation of the αs1-casein complex. Journal of Dairy Research 39 49–53CrossRefGoogle Scholar
Fransson, G.-B. & Lönnerdal, B. 1983 Distribution of trace elements and minerais in human and cow's milk. Pediatrie Research 17 912–915CrossRefGoogle Scholar
Greenberg, B., Groves, M. L. & Dower, H. J. 1984 Human β-casein: amino acid sequence and identification of phosphorylation sites. Journal of Biological Chemistry 259 5132–5138CrossRefGoogle ScholarPubMed
Grosclaude, F., Mahé, M.-F. & Ribadeau-Dumas, B. 1973 [Primary structures of bovine αs1- and β-caseins.] European Journal of Biochemistry 40 323–324CrossRefGoogle Scholar
Groves, M. L. & Gordon, W. G. 1970 The major component of human casein: a protein phosphorylated at different levels. Archives of Biochemistry and Biophysics 140 47–51CrossRefGoogle ScholarPubMed
Hambidge, K. M., Walravens, P. A., Casey, C. E., Brown, R. M. & Bender, C. 1979 Plasma zinc concentrationsof breast-fed infants. Journal of Pediatrics 94 607–608CrossRefGoogle Scholar
Hambraeus, L. 1982 Nutritional aspects of milk proteins, In Developments in Dairy Chemistry-1. Proteins pp. 289–313 (Ed. Fox, P. F.). London: Applied Science PublishersGoogle Scholar
Harzer, G. & Kauer, H. 1982 Binding of zinc to casein. American Journal of Clinical Nutrition 35 981–987CrossRefGoogle ScholarPubMed
Hurley, L. S. & Lönnerdal, B. 1982 Zinc binding in human milk: citrate versus picolinate. Nutrition Reviews 40 65–71CrossRefGoogle ScholarPubMed
Jenness, R. 1973 Caseins and casemate micelles of various species. Netherlands Milk and Dairy Journal 27 251–257Google Scholar
Johnson, P. E. & Evans, G. W. 1978 Relative zinc availability in human breast milk, infant formulas, and cow's milk. American Journal of Clinical Nutrition 31 416–421CrossRefGoogle ScholarPubMed
Klotz, I. M. & Hunston, D. L. 1971 Properties of graphical representations of multiple classes of binding sites. Biochemistry 10 3065–3069CrossRefGoogle ScholarPubMed
Law, B. A. & Reiter, B. 1977 The isolation and bacteriostatic properties of lactoferrin from bovine milk whey. Journal of Dairy Research 44 595–599CrossRefGoogle ScholarPubMed
Lönnerdal, B., Cederblad, Å., Davidsson, L. & Sandström, B. 1984 The effect of individual components of soy formula and cows' milk formula on zinc bioavailability. American Journal of Clinical Nutrition 40 1064–1070CrossRefGoogle ScholarPubMed
Lönnerdal, B., Hoffman, B. & Hurley, L. S. 1982 Zinc and copper binding proteins in human milk. American Journal of Clinical Nutrition 36 1170–1176CrossRefGoogle ScholarPubMed
Lönnerdal, B., Keen, C. L., Bell, J. G. & Hurley, L. S. 1985 Zinc uptake and retention from chelates and milk fractions, In Trace Elements in Man and Animals – TEMA 5 pp. 427–430. (Eds Mills, C. F., Bremner, I. and Chesters, J. K.) Farnham Royal, England: Commonwealth Agricultural BureauxGoogle Scholar
Lönnerdal, B., Keen, C. L. & Hurley, L. S. 1981 Iron, copper, zinc, and manganese in milk. Annual Review of Nutrition 1 149–174CrossRefGoogle ScholarPubMed
Lönnerdal, B., Stanislowski, A. G. & Hurley, L. S. 1980 Isolation of a low molecular weight zinc binding ligand from human milk. Journal of Inorganic Biochemistry 12 71–78CrossRefGoogle ScholarPubMed
Martin, M. T., Jacobs, F. A. & Brushmiller, J. G. 1984 Identification of copper- and zinc-binding ligands in human and bovine milk. Journal of Nutrition 114 869–879CrossRefGoogle ScholarPubMed
McGann, T. C. A., Buchheim, W., Kearney, R. D. & Richardson, T. 1983 Composition and ultrastructure of calcium phosphate–citrate complexes in bovine milk Systems. Biochimica et Biophysica Acta 760 415–420CrossRefGoogle ScholarPubMed
Nagasawa, T., Kiyosawa, I. & Kuwahara, K. 1970 Human casein. II. Isolation of human β-casein fraction and human β-casein B. Journal of Dairy Science 53 136–145CrossRefGoogle ScholarPubMed
Nichol, L. W. & Winzor, D. J. 1976 Ligand-induced polymerization. Biochemistry 15 3015–3019CrossRefGoogle ScholarPubMed
Parker, T. G. & Dalgleish, D. G. 1981 Binding of calcium ions to bovine β-casein. Journal of Dairy Research 48 71–76CrossRefGoogle ScholarPubMed
Peters, T. 1985 Serum albumin. Advances in Protein Chemistry 37 161–245CrossRefGoogle ScholarPubMed
Ribadeau Dumas, B., Brignon, G., Grosclaude, F. & Mercier, J.-C. 1972 [Prirnary structure of bovine β-casein. Complete amino acid sequence.] European Journal of Biochemistry 25 505–514CrossRefGoogle Scholar
Roth, H. P. & Kirchgessner, M. 1985 Utilization of zinc from picolinic or citric acid complexes in relation to dietary protein source in rats. Journal of Nutrition 115 1641–1649CrossRefGoogle ScholarPubMed
Sandström, B., Cederblad, Å. & Lönnerdal, B. 1983 a Zinc absorption from human milk, cow's milk and infant formulas. American Journal of Diseases of Children 137 726–729Google ScholarPubMed
Sandström, B., Keen, C. L. & Lönnerdal, B. 1983 b An experimental model for studiesof zinc bioavailability from milk and infant formulas using extrinsic labelling. American Journal of Clinical Nutrition 38 420–428CrossRefGoogle Scholar
Singh, H., Flynn, A. & Fox, P. F. 1988 Binding of zinc to colloidal calcium phosphate in human and cow's milks, In Trace Elements in Man and Animals – TEMA 6. New York: Plenum Publishing Co. In press.Google Scholar
Singh, H., Flynn, A. & Fox, P. F. 1989 Zinc binding in bovine milk. Journal of Dairy Research 56 249–263CrossRefGoogle ScholarPubMed
Swaisgood, H. E. 1982 Chemistry of milk protein, In Developments in Dairy Chemistry-1. Proteins pp. 1–59 (Ed. Fox, P. F.). London: Applied Science PublishersGoogle Scholar
Waugh, D. F., Slattery, C. W. & Creamer, L. K. 1971 Binding of cations to caseins. Site binding, Donnan binding and System characteristics. Biochemistry 10 817–823CrossRefGoogle ScholarPubMed
Zittle, C. A. & Custer, J. H. 1963 Purification and some of the properties of αs1 casein and k−casein. Journal of Dairy Science 46 1183–1188Google Scholar