Hostname: page-component-586b7cd67f-dlnhk Total loading time: 0 Render date: 2024-11-28T14:07:55.445Z Has data issue: false hasContentIssue false
  • English
  • Français

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
Get access Rights & Permissions [Opens in a new window]

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

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

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