Nonruminant Nutrition: Finishing Pigs - Additives & Energy

in the complexes formed as a consequence of heat treatment. BLG contains five Cys residues and KCN contains 2 Cys residues, and thus there is a large number of combinations of possible disulfide bondings. Reacting reduced KCN with DTNB (dithiobisnitrobenzoic acid) gives KCN molecules containing activated Cys groups. Reacting partially reduced BLG with these derivatives gave a range of products. These were separated and the fraction that contained material with a mass of about 35 KDa was hydrolyzed with trypsin. Among the products were peptides with masses corresponding the peptides BLG148-162 SS KCN87-97 and BLG148-162 SS KCN11-16. The identity of the peptides was verified by partial sequencing of both the intact peptides and the reduced peptides using ESI-MS-MS. A heated milk sample was analyzed and these peptides were identified in a trypsin-treated sample of the mixture of proteins and there was significantly more disulfide-bonded KCN87-97 than KCN11-16 in the mixture. The existence of other possible disulfide bonding patterns involving Cys 66, 106, 119, or 121 of BLG, and Cys 11 or 88 of KCN are being explored.