Characterization and proteolytic origins of specific peptides appearing during lipopolysaccharide experimental mastitis.
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.
Laboratoire de Sciences Animales, U.C. INRA 12 340, Ecole Nationale Supérieure d'Agronomie et des Industries Alimentaires, 54 505 Vandoeuvre-lès-Nancy, France. fatima.moussaoui@ensaia.nancy-inpl.fr
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F
Moussaoui
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F
Laurent
J M
JM
Girardet
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G
Humbert
J L
JL
Gaillard
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Le Roux
D000595:Amino Acid Sequence; D000818:Animals; D002364:Caseins / Q000737:chemistry / Q000378:metabolism; D002417:Cattle; D010450:Endopeptidases / Q000378:metabolism*; D004926:Escherichia coli; D005260:Female; D006868:Hydrolysis; D019272:Leukocyte Elastase / Q000378:metabolism; D008070:Lipopolysaccharides / Q000008:administration & dosage; D008414:Mastitis, Bovine / Q000139:chemically induced / Q000378:metabolism*; D008892:Milk / Q000166:cytology / Q000201:enzymology; D008969:Molecular Sequence Data; D009504:Neutrophils / Q000201:enzymology; D010446:Peptide Fragments / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism
D002364:Caseins; D008070:Lipopolysaccharides; D010446:Peptide Fragments; D010450:Endopeptidases; D019272:Leukocyte Elastase