| Autor: |
Malkoski, Marina, Dashper, Stuart G., O'Brien-Simpson, Neil M., Talbo, Gert H., Macris, Mary, Cross, Keith J., Reynolds, Eric C. |
| Zdroj: |
Antimicrobial Agents and Chemotherapy; August 2001, Vol. 45 Issue: 8 p2309-2315, 7p |
| Abstrakt: |
ABSTRACTCaseinomacropeptide (CMP) is a heterogeneous C-terminal fragment (residues 106 to 169) of bovine milk κ-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 mutansandPorphyromonas gingivalisand against Escherichia coli. CMP was fractionated using reversed-phase high-performance liquid chromatography (RP-HPLC), and each fraction was tested for activity against S. mutansin 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 κ-casein (residues 106 to 169) [κ-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)149κ-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)149κ-casein-A(138–158) and its nonphosphorylated counterpart κ-casein-A(138–158) were chemically synthesized and tested for antibacterial activity. The synthetic Ser(P)149κ-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. |
| Databáze: |
Supplemental Index |
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