Characterization and proteolytic origins of specific peptides appearing during lipopolysaccharide experimental mastitis.

Abstract

Based on the compositional change of the proteose peptone fraction, proteolysis was studied over time following lipopolysaccharide-induced experimental mastitis. Electrophoresis of the proteose peptone fraction revealed many degradation products. Five peptides were identified by amino-terminal sequencing as internal fragments of beta-, kappa-, alpha(s1)-, and alpha(s2)-casein that were generated by somatic cell proteases. Although kappa-casein is considered particularly resistant to endogenous proteolysis, a kappa-casein peptide was electrophoretically isolated in association with a beta-casein fragment. The in vitro kinetic studies of caseinate hydrolysis by elastase, one of the main polymorphonuclear neutrophil (PMN) proteases, suggested that the beta-casein peptide might be generated by elastase. In addition, elastase activity in milk PMN was higher during the inflammation of the mammary gland than prior to infusion.

• Authors: F Moussaoui, F Laurent, J M Girardet, G Humbert, J L Gaillard, Y Le Roux
• Journal: Journal of dairy science (J Dairy Sci) Vol. 86 Issue 4 Pg. 1163-70 (Apr 2003) ISSN: 0022-0302 [Print] United States
• PMID: 12741540 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Caseins
• Lipopolysaccharides
• Peptide Fragments
• Endopeptidases
• Leukocyte Elastase

Topics

• Amino Acid Sequence
• Animals
• Caseins (chemistry, metabolism)
• Cattle
• Endopeptidases (metabolism)
• Escherichia coli
• Female
• Hydrolysis
• Leukocyte Elastase (metabolism)
• Lipopolysaccharides (administration & dosage)
• Mastitis, Bovine (chemically induced, metabolism)
• Milk (cytology, enzymology)
• Molecular Sequence Data
• Neutrophils (enzymology)
• Peptide Fragments (analysis, chemistry, metabolism)