AAC
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Malkoski, M.
Right arrow Articles by Reynolds, E. C.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Malkoski, M.
Right arrow Articles by Reynolds, E. C.

Antimicrobial Agents and Chemotherapy, August 2001, p. 2309-2315, Vol. 45, No. 8
0066-4804/01/$04.00+0   DOI: 10.1128/AAC.45.8.2309-2315.2001
Copyright © 2001, American Society for Microbiology. All rights reserved.

Kappacin, a Novel Antibacterial Peptide from Bovine Milk

Marina Malkoski,1 Stuart G. Dashper,1 Neil M. O'Brien-Simpson,1 Gert H. Talbo,1 Mary Macris,2 Keith J. Cross,1 and Eric C. Reynolds1,*

School of Dental Science, The University of Melbourne, Melbourne, Victoria 3000,1 and Howard Florey Institute of Experimental Physiology and Medicine, The University of Melbourne, Melbourne, Victoria 3101,2 Australia

Received 18 September 2000/Returned for modification 30 January 2001/Accepted 9 May 2001

Caseinomacropeptide (CMP) is a heterogeneous C-terminal fragment (residues 106 to 169) of bovine milk kappa -casein composed of glycosylated and phosphorylated forms of different genetic variants. We have demonstrated that CMP has growth-inhibitory activity against the oral opportunistic pathogens Streptococcus mutans and Porphyromonas gingivalis and against Escherichia coli. CMP was fractionated using reversed-phase high-performance liquid chromatography (RP-HPLC), and each fraction was tested for activity against S. mutans in a 96-well-plate broth assay. Fractions were characterized by N-terminal sequence analysis and mass spectrometry. The active form of CMP was shown to be the nonglycosylated, phosphorylated kappa -casein (residues 106 to 169) [kappa -casein(106-169)], which we have designated kappacin. Endoproteinase Glu-C was used to hydrolyze CMP, and the generated peptides were separated using RP-HPLC and gel filtration-HPLC and then tested for activity against S. mutans. The peptide Ser(P)149kappa -casein-A(138-158) was the only peptide generated by endoproteinase Glu-C digestion that exhibited growth-inhibitory activity. Peptides corresponding to the sequences of the inhibitory peptide Ser(P)149kappa -casein-A(138-158) and its nonphosphorylated counterpart kappa -casein-A(138-158) were chemically synthesized and tested for antibacterial activity. The synthetic Ser(P)149 kappa -casein-A(138-158) displayed growth-inhibitory activity against S. mutans (MIC, 59 µg/ml [26 µM]). The nonphosphorylated peptide, however, did not inhibit growth at the concentrations tested, indicating that phosphorylation is essential for activity.


* Corresponding author. Mailing address: School of Dental Science, The University of Melbourne, 711 Elizabeth St., Melbourne, Victoria 3000, Australia. Phone: 61 3 9341 0270. Fax: 61 3 9341 0236. E-mail: e.reynolds{at}dent.unimelb.edu.au.


Antimicrobial Agents and Chemotherapy, August 2001, p. 2309-2315, Vol. 45, No. 8
0066-4804/01/$04.00+0   DOI: 10.1128/AAC.45.8.2309-2315.2001
Copyright © 2001, American Society for Microbiology. All rights reserved.



This article has been cited by other articles:




Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
Clin. Vaccine Immunol. Clin. Microbiol. Rev.
J. Clin. Microbiol. ALL ASM JOURNALS

Copyright © 2001 by the American Society for Microbiology. All rights reserved.