Kiyozo Hasegawa

Limits and Sites of Lysinoalanine Formation in Lysozyme, α-Lactalbumin and αs1- and β-Caseins by Alkali Treatment

Lysinoalanine was determined by gas chromatography. Lysinoalanine formation in lysozyme depended on alkali concentration, pH, temperature and exposure time. The upper limits of lysinoalanine formation in lysozyme and α-lactalbumin were related to the number of lysine residues with a cystine disulfide bond in the adjacent position rather than the individual contents of these residues. In cases of αsl- and β-caseins, the upper limits were related to the number of phosphoserine residues, regardless of their sequential relationship to lysine residues. Gel electrophoresis suggested that intermolecular cross-linking took place in the α-lactalbumin and caseins.