Journal
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
Volume 59, Issue 1, Pages 444-449Publisher
AMER CHEMICAL SOC
DOI: 10.1021/jf104298y
Keywords
alpha-Lactalbumin; molten globule; dityrosine; horseradish peroxidase; protein cross-linking
Funding
- Netherlands Organisation for Scientific Research (NWO) [053.65.001]
Ask authors/readers for more resources
The peroxidase-mediated oxidation of calcium-depleted bovine a-lactalbumin generates a mixture of covalently bound protein oligomers with interesting foaming properties. Here, we isolated the initially formed covalent alpha-lactalbumin dimer and studied its mode of cross-linking. Liquid chromatography-Fourier transform mass spectrometry (LC-FTMS) of proteolytic digests revealed the unambiguous identification of a peroxidase-catalyzed covalent link between Tyr18 and Tyr50. This shows that, although the radical reaction is often regarded as a random reaction, the initial product formation is specific. Protein structural modeling indicates that the conjugation reaction between these tyrosines is sterically favored and involves initial noncovalent protein complex formation through charge compensation, facilitating intermolecular cross-linking. The identification of the Tyr18 Tyr50 cross-link supports the view that the peroxidase-mediated oxidation of apo alpha-lactalbumin is a sequential process, involving the formation of linear trimers and higher order oligomers.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available