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Proteinases in normal bovine milk and their action on caseins

Published online by Cambridge University Press:  01 June 2009

Anthony T. Andrews
Affiliation:
National Institute for Research in Dairying, Shinfield, Reading RG2 9 AT, U.K.

Summary

Native proteolytic enzymes in good quality normal bovine milk readily hydrolyscd the caseins during incubation or storage, producing the γ-caseins, proteosc-peptone components 5 (PP5) and 8-fast (PP8F) and a considerable number of other unidentified fragments, many of which were also subsequently found in the proteose-pcptone fraction. The rate of casein hydrolysis was greater in pasteurized than in raw milk, with β-casein being slightly more susceptible to attack than αs1-easein. Measurements of γ-cascin and proteose-peptone formation have been made and it was found that PP5 was an intermediate product that was subject to further proteolysis while PP8F was a stable end-product. With the exception of component 3 (PP3), virtually all constituents of the proteose-peptone fraction increased during storage and appeared to be products of the action of proteolytic enzymes. Further evidence was obtained from the effects of various inhibitors that the principal proteinase of normal milk is plasmin, but slight differences were apparent between the protein breakdown patterns induced by storage and by added plasmin, which was consistent with the presence of more than one proteinase. Incubations in the presence of soya bean trypsin inhibitor to prevent plasmin action clearly revealed that another enzyme(s) was also involved.

Type
Original Articles
Copyright
Copyright © Proprietors of Journal of Dairy Research 1983

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References

REFERENCES

Anderson, M. & Andrews, A. T. 1977 Progressive changes in individual milk protein concentrations associated with high somatic cell counts. Journal of Dairy Research 44 223235CrossRefGoogle ScholarPubMed
Andrews, A. T. 1978 a The composition, structure and origin of proteose-peptone component 5 of bovine milk. European Journal of Biochemistry 90 5965CrossRefGoogle ScholarPubMed
Andrews, A. T. 1978 b The composition, structure and origin of proteose-peptone component 8F of bovine milk. European Journal of Biochemistry 90 6771CrossRefGoogle ScholarPubMed
Chen, J. H. & Ledford, R. A. 1971 Purification and characterization of milk protease. Journal of Dairy Science 54 763Google Scholar
Davies, D. T. & Law, A. J. R. 1977 An improved method for the quantitative fractionation of casein mixtures using ion-exchange chromatography. Journal of Dairy Research 44 213221CrossRefGoogle Scholar
Eigel, W. N. 1977 Effect of bovine plasmin on αs1-β and κ-A caseins. Journal of Dairy Science 60 13991403CrossRefGoogle 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 United States of America 76 22442248CrossRefGoogle ScholarPubMed
Eigel, W. N. & Keenan, T. W. 1979 Identification of proteose peptone component 8-slow as a plasmin-derived fragment of bovine β-casein. International Journal of Biochemistry 10 529535CrossRefGoogle ScholarPubMed
Gordon, W. G. & Groves, M. L. 1975 Primary sequence of beta, gamma and minor caseins. Journal of Dairy Science 58 574582CrossRefGoogle Scholar
Gordon, W. G., Groves, M. L., Greenberg, R., Jones, S. B., Kalan, E. B., Peterson, R. F. & Townend, R. E. 1972 Probable identification of γ-, TS-, R- and S-caseins as fragments of γ-casein. Journal of Dairy Science 55 261263CrossRefGoogle Scholar
Halpaap, I., Reimerdes, E. H. & Klostermeyer, H. 1977 [Milk proteinases. VI. Comparative isolation of plasminogen from bovine blood and a proteinase from cow's milk.] Milchwissenschaft 32 341346Google Scholar
Humhert, G. & Alais, C. 1979 Review of the progress of dairy science. The milk proteinase system. Journal of Dairy Research 46, 559571CrossRefGoogle Scholar
Kaminogawa, S., Mizobuchi, H. & Yamauchi, K. 1972 Comparison of bovine milk protease with plasmin. Agricultural and Biological Chemistry 36 21632167CrossRefGoogle Scholar
Kaminogawa, S. & Yamauchi, K. 1972 Acid protease of bovine milk. Agricultural and Biological Chemistry 36 23512356CrossRefGoogle Scholar
Kaminogawa, S., Yamauchi, K. & Tsugo, T. 1969 Properties of milk protease concentrated from acidprecipitated casein. Japanese Journal of Zootechnical Science 40 559565Google Scholar
Kester, J. J. & Brunner, J. R. 1980 Isolation and comparison of glycoprotein fractions from proteose-peptone and milk fat globule membrane. Journal of Dairy Science 63 (Supplement 1) 4445Google Scholar
Law, B. A. 1979 Reviews of the progress of Dairy Science. Enzymes of psychrotrophic bacteria and their effects on milk and milk products. Journal of Dairy Research 46 573588CrossRefGoogle Scholar
Noomen, A. 1975 Proteolytic activity of milk protease in raw and pasteurized cow's milk. Netherlands Milk and Dairy Journal 29 153161Google Scholar
Reimerdes, E. H., Halpaap, I. & Klostermeyer, H. 1981 a [Milk proteinases. 8. Comparative characterization of plasmin from cows′ blood with a serine proteinase from cows′ milk.] Milchwissenschaft 36 1922Google Scholar
Reimerdes, E. H., Halpaap, I. & Klostermeyer, H. 1981 b [Milk proteinases. 10. Enzyme-kinetic comparison of bovine plasmin with two milk proteinases.] Milchwissenschaft 36 7379Google Scholar
Reimerdes, E. H., Klostermeyer, H. & Sayk, E. 1976 [Milk proteinases. 7. Fractionation of components of the proteinase inhibitor system in milk.] Milchwissenschaft 31 329334Google Scholar
Reimerdes, E. H., Petersen, F. & Kielwein, G. 1979 [Milk proteinases. 9. Proteolytic activity profiles of casein micelles, milk serum, blood serum and Pseudomonas fluorescens] Milchwissenschaft 34 548551Google Scholar
Snoeren, T. H. M. & Van Riel, J. A. M. 1979 Milk proteinase, its isolation and action on αs2- and β-casein. Milchwissenschaft 34 528531Google Scholar
Visser, S. 1981 Proteolytic enzymes and their action on milk proteins. A review. Netherlands Milk and Dairy Journal 35 6588Google Scholar
Weinstein, M. J. & Doolitle, R. F. 1972 Differential specificities of thrombin, plasmin and trypsin with regard to synthetic and natural substrates and inhibitors. Biochimica el Biophysica Acta 258 577590CrossRefGoogle ScholarPubMed
Yamauchi, K. & Kaminogawa, S. 1972 Decomposition of milk proteins by milk protease. Agricultural and Biological Chemistry 36 249254CrossRefGoogle Scholar