Hostname: page-component-5c6d5d7d68-qks25 Total loading time: 0 Render date: 2024-08-08T11:22:55.340Z Has data issue: false hasContentIssue false

Molecular weights of subunit components of bovine casein micelles

Published online by Cambridge University Press:  01 June 2009

Tomotada Ono
Affiliation:
Department of Agricultural Chemistry, Iwate University, Morioka 020, Japan
Toshio Takagi
Affiliation:
Institute for Protein Research, Osaka University, Suita, Osaka 565, Japan

Summary

Using either Sephacryl S-300 or TSK-G4000SW gel chromatography, the larger of the two major components of bovine casein micelles (F2) was eluted at the same retention time irrespective of sample concentration and column temperature. Its mol. wt was estimated to be 500K by examination of the eluate from a TSK-gel G4000SW column using a low-angle laser light-scattering photometer and a precision differential refractometer. With the second component (F3), retention time in Sephacryl gel chromatography was significantly affected by both sample concentra-tion and volume applied. Limiting retention times for F3 could be obtained by extrapolation of these two parameters to higher and lower values, and corresponded to those of water-soluble protein with mol. wt 200K and 100K respectively. Approach to sedimentation equilibrium technique at the above limiting sample concentrations gave values of F3 consistent with the above molecular weight. Sephacryl gel chromatography at either low sample concentration or low column temperature resulted in a new component being eluted at a position of mol. wt 25K

Type
Original Articles
Copyright
Copyright © Proprietors of Journal of Dairy Research 1986

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

Archibald, W. J. 1947 A demonstration of some new methods of determining molecular weights from the data of the ultracentrifuge. Journal of Physical and Colloid Chemistry 51 12041214CrossRefGoogle ScholarPubMed
Buchheim, W. & Welsch, U. 1973 Evidence for the submicellar composition of casein micelles on the basis of electron microscopical studies. Netherlands Milk and Dairy Journal 27 163180Google Scholar
Creamer, L. K. & Berry, G. P. 1975 A study of the properties of dissociated bovine casein micelles. Journal of Dairy Research 42 169183CrossRefGoogle Scholar
Eigel, W. N., Hofmann, C. J., Chibber, B. A. K., Tomich, J. M., Keenan, T. W. & Mertz, E. T. 1979 Plasmin-mediated proteolysis of casein in bovine milk. Proceedings of the National Academy of Sciences of the USA 76 22442248CrossRefGoogle ScholarPubMed
Heth, A. A. & Swaisgood, H. E. 1982 Examination of casein micelle structure by a method for reversible covalent immobilization. Journal of Dairy Science 65 20472054CrossRefGoogle Scholar
Kaye, W., Havilik, J. & Madaniel, J. B. 1971 Light scattering measurements on liquids at small angles. Polymer Letters 9 695699CrossRefGoogle Scholar
Maezawa, S., Hayashi, Y., Nakae, T., Ishii, J., Kameyama, K. & Takagi, T. 1983 Determination of molecular weight of membrane proteins by the use of low-angle laser light scattering combined with high-performance gel chromatography in the presence of a non-ionic surfactant. Biochimica et Biophysica Acta 747 291297CrossRefGoogle Scholar
Ono, T., Furuyama, T. & Odagiri, S. 1983 a Formation of artificial casein micelles. Agricultural and Biological Chemistry 47 221226Google Scholar
Ono, T., Odagiri, S. & Takagi, T. 1983 b Separation of the submicelles from micellar casein by high performance gel chromatography on a TSK-GEL G4000SW column. Journal of Dairy Research 50 3744CrossRefGoogle Scholar
Schmidt, D. G. & Buchheim, W. 1970 [An electron-microscopic investigation of the substructure of the casein micelles in cow's milk.] Milchwissenschaft 25 596600Google Scholar
Siegel, L. M. & Monty, K. J. 1966 Determination of molecular weights and frictional ratios of proteins in impure systems by use of gel filtration and density gradient centrifugation. Application to crude preparations of sulfite and hydroxylamine reductases. Biochimica et Biophysica Acta 112 346362CrossRefGoogle Scholar
Slattery, C. W. 1979 A phosphate-induced sub-micelle - micelle equilibrium in reconstituted casein micelle systems. Journal of Dairy Research 46 253258CrossRefGoogle ScholarPubMed
Sober, H. A. (Ed.) 1970 Handbook of Biochemistry, 2nd edn, pp. C4C25. Cleveland, OH: Chemical Rubber CoGoogle Scholar
Takagi, T. 1981 Confirmation of molecular weight of Aspergillus oryzae α-amylase using the low angle laser light scattering technique in combination with high pressure silica gel chromatography. Journal of Biochemistry 89 363368CrossRefGoogle Scholar
Waugh, D. F., Creamer, L. K., Slattery, C. W. & Dresdner, G. W. 1970 Core polymers of casein micelles. Biochemistry 9 786795CrossRefGoogle ScholarPubMed
Waugh, D. F. & Talbot, B. 1971 Equilibrium casein micelle systems. Biochemistry 10 41534162CrossRefGoogle ScholarPubMed