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Purification and thermostability of β-galactosidase (lactase) from an autolytic strain of Streptococcus salivarius subsp. thermophilus

Published online by Cambridge University Press:  01 June 2009

Byeong-Seon Chang  and
Raymond R. Mahoney
Byeong-Seon Chang
Affiliation:
Department of Food Science and Nutrition, Massachusetts Agricultural Experiment Station, University of Massachusetts, Amherst, MA 01003, USA
Raymond R. Mahoney
Affiliation:
Department of Food Science and Nutrition, Massachusetts Agricultural Experiment Station, University of Massachusetts, Amherst, MA 01003, USA
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Summary

β-Galactosidase from an autolytic strain of Streptococcus salivarius subsp. thermophilus was purified 109-fold to near homogeneity. The yield of purified enzyme was 41% and the specific activity was 592 0-nitrophenyl β-D-galactopyranoside U/mg at 37 °C. Two isozymes were present, but only one subunit was detected, having a mol. wt of 116000. Enzyme stability was 37–83 times greater in milk than in buffer in the range 60–65 °C. At 60 °C the half-life in milk was 146 min. Denaturation in buffer was first-order, but in milk the overall reaction order with respect to enzyme concentration was ˜ 0·5. The activation energy for denaturation was 453 kJ/mol in milk and 372 kJ/mol in buffer. In milk the activation energy for lactose hydrolysis was 35·1 kJ/mol.

Type
Original Articles
Information
Journal of Dairy Research , Volume 56 , Issue 1 , February 1989 , pp. 117 - 127
Copyright
Copyright © Proprietors of Journal of Dairy Research 1989

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References

REFERENCES

Contaxis, C. C. & Reithel, F. J. 1974 Studies on protein multimers. VII. Stabilization of Escherichia coli β-galactosidase by a 260 nm absorbing compound in crude preparations. Archives of Biochemistry and Biophysics 160 588–594CrossRefGoogle ScholarPubMed
Gekas, V. & López-Leiva, M. 1985 Hydrolysis of lactose: a literature review. Process Biochemistry 20(2) 2–12Google Scholar
Greenberg, N. A. & Mahoney, R. R. 1982 Production and characterization of β-galactosidase from Streptococcus thermophilus. Journal of Food Science 47 1824–1828, 1835CrossRefGoogle Scholar
Greenberg, N. A., Wilder, T. & Mahoney, R. R. 1985 Studies on the thermostability of lactase (Streptococcus thermophilus) in milk and sweet whey. Journal of Dairy Research 52 439–449CrossRefGoogle Scholar
Griffiths, M. W. & Muir, D. D. 1978 Properties of a thermostable β-galactosidase from a thermophilic Bacillus: comparison of the enzyme activity of whole cells, purified enzyme and immobilised whole cells. Journal of the Science of Food and Agriculture 29 753–761CrossRefGoogle ScholarPubMed
Hemme, D., Nardi, M. & Jette, D. 1980 [Beta-galactosidases and phospho-beta-galactosidases of Streptococcus thermophilus.] Lait 60 595–618CrossRefGoogle Scholar
Hill, C. G. & Grieger-Block, R. A. 1980 Kinetic data: generation, interpretation, and use. Food Technology 34 56–66Google Scholar
Kobayashi, T., Hirose, Y., Ohmiya, K., Shimizu, S. & Uchino, F. 1978 Thermostable β-galactosidase from Bacillus acidocaldarius and its immobilization. Journal of Fermentation Technology 56 309–314Google Scholar
Lowry, O. H., Rosebrough, N. J., Farr, A. L. & Randall, R. J. 1951 Protein measurement with the Folin phenol reagent. Journal of Biological Chemistry 193 265–275CrossRefGoogle ScholarPubMed
Mahoney, R. R. 1985 Modification of lactose and lactose-containing dairy products with β-galactosidase. In Developments in Dairy Chemistry-3. Lactose and Minor Constituents pp. 69–109 (Ed. Fox, P. F.) London: Elsevier Applied ScienceGoogle Scholar
Mahoney, R. R. & Whitaker, J. R. 1978 Purification and physicochemical properties of β-galactosidase from Kluyveromyces fragilis. Journal of Food Science 43 584–591CrossRefGoogle Scholar
Mozaffar, Z., Nakanishi, K., Matsuno, R. & Kamikubo, T. 1984 Purification and properties of β-galactosidases from Bacillus circulans. Agricultural and Biological Chemistry 48 3053–3061Google Scholar
Ramana Rao, M. V. & Dutta, S. M. 1981 Purification and properties of β-galactosidase from Streptococcus thermophilus. Journal of Food Science 46 1419–1423Google Scholar
Smart, J. B., Crow, V. L. & Thomas, T. D. 1985 Lactose hydrolysis in milk and whey using β-galactosidase from Streptococcus thermophilus. New Zealand Journal of Dairy Science and Technology 20 43–56Google Scholar
Smart, J. B. & Richardson, B. 1987 Molecular properties and sensitivity to cations of β-galactosidase from Streptococcus thermophilus with four enzyme substrates. Applied Microbiology and Biotechnology 26 177–185CrossRefGoogle Scholar
Somkuti, G. A. & Steinberg, D. H. 1979 β-Galactoside galactohydrolase of Streptococcus thermophilus: induction, purification, and properties. Journal of Applied Biochemistry 1 357–368.Google Scholar
Thomas, T. D. & Crow, V. L. 1983 Lactose and sucrose utilization by Streptococcus thermophilus. FEMS Microbiology Letters 17 13–17CrossRefGoogle Scholar
Weber, K. & Osborn, M. 1975 Proteins and sodium dodecyl sulfate: Molecular weight determination on polyacrylamide gels and related procedures. In The Proteins, 3rd edn, Vol. 1, pp. 180–221 (Eds Neurath, H. and Hill, R. L.) New York: Academic Press.Google Scholar