Skip to main content Accessibility help

A qualitative screening procedure for the detection of casein hydrolysis by bacteria, using sodium dodecyl sulphate polyacrylamide gel electrophoresis

  • Susan H. A. Hill (a1) and Michael J. Gasson (a1)


Incubation of bacteria with casein at 30 °C (pH 7·2) resulted in the formation of a number of peptide fragments. The peptides were separable when subjected to electrophoresis. A proteinase-positive strain of Streptococcus lactis preferentially hydrolysed the β-casein moiety of whole casein, and after incubation for 5 min produced a characteristic pattern of four peptides on sodium dodecyl sulphate (SDS) polyacrylamide gels. After 30 min incubation only one peptide remained. This single polypeptide was then further hydrolysed to produce one (60 min) and eventually two (120 min) lower molecular weight peptides. Hydrolysis was generally complete after about 480 min. Two proteinase-negative variants of this strain did not hydrolyse casein. Crude proteinase preparations gave the same characteristic peptide patterns. SDS-polyacrylamide gel electrophoresis was used to screen more proteinase-positive strains of Str. Lactis for casein hydrolysing activity. Of those so far tested all produced the same peptide patterns from β-casein. Proteinase negative variants of all these strains did not hydrolyse casein.



Hide All
Andrews, A. T. 1984 Detection and measurement by the electrophoretic pattern of peptides produced by caseinolysis. In Methods of Enzymatic Analysis 3rd edn 5 227285 (Eds Bergmeyer, J. and Grassl, M.), Weinheim: Verlag Chemie
Exterkate, F. A. 1976 Comparison of strains of Streptococcus cremoris for proteolytic activities associated with the cell wall. Netherlands Milk and Dairy Journal 30 95105
Gasson, M. J. 1983 Plasmid complements of Streptococcus lactis NCDO 712 and other lactic streptococci after protoplast-induced curing. Journal of Bacteriology 154 19
Gasson, M. J. & Davies, F. L. 1984 The genetics of dairy lactic-acid bacteria. In Advances in the Microbiology and Biochemistry of Cheese and Fermented Milk pp. 99126 (Eds Davies, F. L. & Law, B. A.) London: Elsevier Applied Science.
Hugenholtz, J., Exterkate, F. & Konings, W. N. 1984 The proteolytic systems of Streptococcus cremoris: an immunological analysis. Applied and Environmental Microbiology 48 11051110
Jenkinson, H. F., Sawyer, W. D. & Mandelstam, J. 1981 Synthesis and order of assembly of spore coat proteins in Bacillus suibtilis. Journal of General Microbiology 123 116
Laemmli, U. K. & Favre, M. 1973 Maturation of the head of bacteriophage T4. 1. DNA packaging events. Journal of Molecular Biology 80 575599
Law, B. A. & Kolstad, J. 1983 Proteolytic systems in lactic acid bacteria. Antonie van Leeuwenhoek Journal of Microbiology 49 225245
Law, B. A. & Wigmore, A. S. 1982 Microbial proteinases as agents for accelerated cheese ripening. Journal of the Society of Dairy Technology 35 7576
Mills, O. E. & Thomas, T. D. 1980 Bitterness development in Cheddar cheese: Effect of the level of starter proteinase. New Zealand Journal of Dairy Science and Technology 15 131141
Porzio, M. A. & Pearson, A. M. 1975 Isolation of an extracellular neutral proteinase from Pseudomonas fragi. Biochimica et Biophysica Acta 384 235241
Stadhouders, T. 1961 The hydrolysis of protein during the ripening of cheese: some methods to accelerate the ripening. Netherlands Milk and Dairy Journal 15 161164
Thomas, T. D., Jarvis, B. D. W. & Skipper, N. A. 1974 Localization of proteinase(s) near the cell surface of Streptococcus lactis. Journal of Bacteriology 118 329333
Thomas, T. D. & Mills, O. E. 1981 Proteolytic enzymes of starter bacteria. Netherlands Milk and Dairy Journal 35 255273
Umemoto, Y. & Itoh, H. 1981 Characterization of cell surface proteinases of lactic acid bacteria. Netherlands Milk and Dairy Journal 35 333337
Visser, S. 1981 Proteolytic enzymes and their action on milk proteins. A review. Netherlands Milk and Dairy Journal 35 6588

Related content

Powered by UNSILO

A qualitative screening procedure for the detection of casein hydrolysis by bacteria, using sodium dodecyl sulphate polyacrylamide gel electrophoresis

  • Susan H. A. Hill (a1) and Michael J. Gasson (a1)


Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed.