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.
Moussaoui
F
F
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
Laurent
F
F
Girardet
J M
JM
Humbert
G
G
Gaillard
J L
JL
Le Roux
Y
Y
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