This paper is only available as a PDF. To read, Please Download here.
Abstract
The composition of bovine casein micelles was analyzed by 31P magic angle spinning solid-state nuclear magnetic resonance spectroscopy. By looking at isotropic and anisotropic 31P chemical shift parameters, resonance line shapes, the combination of single-pulse and 1H to 31P cross-polarization spectra, and comparison with spectra for various model compounds combined with multiple-component simulation and iterative fitting procedures, we were able to identify and quantify a variety of inorganic and organic phosphates in the micelles. These include phosphates from mobile and immobile inorganic hydroxyapatite-type phosphates as well as phosphates from κ-casein and the Ca2+-binding phosphoserines from αs1−, αs2−, and β-casein. This information is discussed in relation to previous knowledge and various models for the colloid formation.
Key words
References
- Effects of self-association of αs1-casein and its cleavage fractions αs1-casein (136–196) and αs1-casein (1–197), on aromatic circular di-chroic spectra: Comparison with predicted models.Biochim. Bio-phys. Acta. 1999; 1431: 395-409
- High-resolution solid-state NMR of milk products.J. Magn. Reson. Anal. 1996; 2: 267-274
- SIMPSON: A general simulation program for solid-state NMR.J. Magn. Reson. 2000; 147: 296-300
- Solid-state 13C and 31P NMR analysis of urinary stones.J. Urol. 2000; 164: 856-863
- The structure of casein aggregates during renneting studied by indirect Fourier transform and inverse Laplace transformation of static and dynamic light scattering data, respectively.J. Chem. Phys. 1995; 103: 2725-2737
- Molecular chaperone-like properties of an unfolded protein, αs-casein.J. Biol. Chem. 1999; 274: 15505-15509
- Micelle stability: κ-casein structure and function.J. Dairy Sci. 1998; 81: 3004-3012
- Casein micelles as colloids: Surface structures and stabilities.J. Dairy Sci. 1998; 81: 3013-3018
- pH-Induced dissociation of bovine casein micelles. II. Mineral solubilization and its relation to casein release.J. Dairy Res. 1989; 56: 727-735
- An improved method for the quantitative fractionation of casein mixtures using ion-exchange chromatography.J. Dairy Res. 1977; 44: 213-221
- The temperature dependent dissociation of b-casein from bovine casein micelles.J. Dairy Res. 1970; 37: 361
- The caseins of milk as calcium-binding proteins.in: Calcium-Binding Proteins. Vol. 2. CRC Press, Boca Raton, FL1988: 117-137
- Phosphopeptides interacting with colloidal calcium phosphate isolated by tryptic hydrolysis of bovine casein micelles.J. Dairy Res. 1996; 63: 405-422
- A 1H NMR study of bovine casein micelles.Biochem. J. 1985; 228: 273-276
- Structure of casein micelles studied by small-angle neutron scattering.Eur. Biophys. J. 1996; 24: 43-147
- Structure of bovine milk calcium phosphate determined by X-ray absorption spectroscopy.Biochim. Biophys. Acta. 1982; 719: 299-303
- Primary and predicted secondary structure of the caseins in relation to their biological function.Protein Eng. 1988; 2: 251-259
- A core-shell model of calcium phosphate nanoclusters stabilized by β-casein phosphopeptides, derived from sedimentation equilibrium and small-angle X-ray and neutron-scattering measurements.Eur. J. Biochem. 1998; 252: 73-78
- Ability of a β-casein phosphopeptide to modulate the precipitation of calcium phosphate by forming amorphous dicalcium phosphate nanoclusters.Biochem. J. 1996; 314: 1035-1039
- A 1H-NMR study of the casein phosphopeptide αs1-casein (59-79).Biochim. Biophys. Acta. 1995; 1247: 201-208
- A multinuclear, high-resolution NMR study of bovine casein micelles and submicelles.Biophys. Chem. 1990; 38: 87-98
- Determination of the quaternary structure of bovine caseins by small-angle X-ray scattering.Arch Biochem. Biophys. 1988; 266: 548-561
- Rethinking casein micelle structure using electron microscopy.J. Dairy Sci. 1998; 81: 2985-2993
- Phosphorylation of caseins, present evidence for an amino acid triplet code posttranslationally recognized by specific kinases.Biochimie. 1981; 63: 1-17
- Selection of nonprotonated carbon resonances in solid-state nuclear magnetic resonance.J. Am. Chem. Soc. 1979; 101: 5854-5856
- Proton-enhanced NMR of dilute spins in solids.J. Chem. Phys. 1973; 59: 569-590
- The multimeric structure and disulfide-bonding pattern of bovine κ-casein.Eur. J. Biochem. 1992; 207: 215-222
- Disulphide-linked caseins and casein micelles.Int. Dairy J. 1999; 9: 215-218
- Characterization of phosphate sites in native ovine, caprine, and bovine casein micelles and their caseinomacropeptides: A solid-state phosphorus-31 nuclear magnetic resonance and sequence and mass spectrometric study.J. Dairy Sci. 1997; 80: 607-614
- Casein association and micelle formation.in: Fox P.F. Advanced Dairy Chemistry. 1. Proteins. Elsevier Applied Science, London, UK1992: 110-140
- A 1H NMR study of bovine casein micelles. The influence of pH, temperature and calcium ions on micellar structure.J. Dairy Sci. 1989; 56: 417-425
- Relation between micellar and serum casein in bovine milk.J. Dairy Sci. 1968; 51: 1897-1902
- High-resolution variable-temperature 31P NMR of solid calcium phosphates.J. Am. Chem. Soc. 1980; 102: 2637
- Association of caseins and casein micelle structure.in: Fox P.F. Developments in Dairy Chemistry. Elsevier Applied Science, London, UK1982: 61-86
- Subunit structure of casein micelles by small-angle neutron scattering.J. Mol. Biol. 1989; 208: 635-639
- Chemistry of the caseins.in: Fox P.F. Advanced Dairy Chemistry. 1. Proteins. Elsevier Applied Science, London, UK1992: 63-110
- Calcium phosphate formation in vitro. II. Effects of environments on amorphous-crystalline transformation.Arch. Biochem. Biophys. 1970; 140: 318-325
- Calcium phosphate formation in vitro. I. Factors affecting initial phase separation.Arch. Biochem. Biophys. 1970; 140: 307-317
- Solid-state magic angle spinning 31PNMR studies of native casein micelles.Eur. J. Biochem. 1995; 230: 454-459
- A 43Ca and 31P NMR study of the calcium and phosphate equilibria in heated milk solutions.J. Dairy Res. 1990; 57: 355-364
Article info
Publication history
Accepted:
December 1,
2000
Received:
July 31,
2000
Identification
Copyright
© 2001 American Dairy Science Association. Published by Elsevier Inc.
User license
Elsevier user license | How you can reuse
Elsevier's open access license policy

Elsevier user license
Permitted
For non-commercial purposes:
- Read, print & download
- Text & data mine
- Translate the article
Not Permitted
- Reuse portions or extracts from the article in other works
- Redistribute or republish the final article
- Sell or re-use for commercial purposes
Elsevier's open access license policy