Posttranslational ruling of xanthine oxidase activity in bovine milk by its substrates

Journal Article · Fri Nov 23 04:00:00 EST 2007 · Biochemical and Biophysical Research Communications

DOI:https://doi.org/10.1016/j.bbrc.2007.08.188· OSTI ID:21032980

Silanikove, Nissim ^[1]; Shapiro, Fira ^[1]; Leitner, Gabriel ^[2]

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1. Ruminant Physiology, Institute of Animal Science, Agricultural Research Organization, Volcani Center, P.O. Box 6, Bet Dagan 50250 (Israel)
2. National Mastitis Reference Center, Kimron Veterinary Institute, Bet Dagan 50250 (Israel)

The aims of this study were to test the hypothesis that the substrates of xanthine oxidase (XO), xanthine and hypoxanthine, are consumed while the milk is stored in the gland between milkings, and to explore how XO activity responds to bacteria commonly associated with subclinical infections in the mammary gland. Freshly secreted milk was obtained following complete evacuation of the gland and induction of milk ejection with oxytocin. In bacteria-free fresh milk xanthine and hypoxanthine were converted to uric acid within 30 min (T{sub 1/2} {approx} 10 min), which in turn provides electrons for formation of hydrogen peroxide and endows the alveolar lumen with passive protection against invading bacteria. On the other hand, the longer residence time of milk in the cistern compartment was not associated with oxidative stress as a result of XO idleness caused by exhaustion of its physiological fuels. The specific response of XO to bacteria species and the resulting bacteria-dependent nitrosative stress further demonstrates that it is part of the gland immune system.

• OSTI ID: 21032980
• Journal Information: Biochemical and Biophysical Research Communications, Journal Name: Biochemical and Biophysical Research Communications Journal Issue: 3 Vol. 363; ISSN 0006-291X; ISSN BBRCA9
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
BACTERIA
BIOLOGICAL STRESS
CATTLE
HYDROGEN PEROXIDE
HYPOXANTHINE
IMMUNITY
MAMMARY GLANDS
MILK
OXIDASES
OXIDATION
OXYTOCIN
SUBSTRATES
URIC ACID