Yx. Sun et S. Hayakawa, Thermally induced aggregates in mixtures of alpha-lactalbumin with ovalbumins from different avian species, J AGR FOOD, 49(5), 2001, pp. 2511-2517
Interactions between a-lactalbumin (alpha -La) and ovalbumin (OVA) in mixed
systems (1:1 ratios; 2, 4, and 8% w/w total protein, respectively) heated
at pH 7 and 80 degreesC for 15 min were studied using sodium dodecyl sulfat
e-polyacrylamide gel electrophoresis (SDS-PAGE), gel filtration chromatogra
phy (GFC), and competitive enzyme-linked immunosorbent assay (ELISA). Altho
ugh a-La alone did not form aggregates upon heating, it formed large aggreg
ates when heated with OVA. The aggregated molecules eluted at the void volu
me had a molecular mass > 300 kDa. The aggregation process was quantitative
ly affected by different avian OVAs from five species, possessing different
numbers of free sulfhydryl groups. The amount of aggregates (M-w > 300 kDa
) increased in proportion to total protein concentration, and the amount of
intermediate components (M-w < 300 kDa) and monomeric OVA and alpha -La al
so changed, correlating with total protein concentration during heating. Th
e results also indicated that the aggregates and intermediates, which conta
ined dimeric and trimeric alpha -La, were mainly formed by the intermolecul
ar disulfide bonds. The different interactions observed in several avian OV
As may explain heat-induced gelation of various avian OVAs as well as the e
nhancement of heat-induced gelation of OVA by alpha -La.