Functional changes in beta-lactoglobulin upon conjugation with carboxymethyl cyclodextrin.
Bovine beta-lactoglobulin-carboxymethyl cyclodextrin (beta-LG-CMCyD) conjugate was prepared using water-soluble carbodiimide, in an effort to improve the functional properties of the protein. The molar ratio of beta-LG to CMCyD in the conjugate was 1:2. The isoelectric point of the conjugate was 4.1-5.8. Spectroscopic studies indicated that the global conformation of the conjugate was similar to that of native beta-LG. Structural analyses with monoclonal antibodies indicated that there was a conformational change around (15)Val-(29)Ile (beta-sheet). The denaturation temperature of the conjugate was about 77 degrees C, which is about 4 degrees C higher than that of native beta-LG. The beta-LG-CMCyD conjugate maintained retinol-binding activity as strong as that of beta-LG. The emulsifying activity of beta-LG was much improved and the antioxidative activity of beta-LG was maintained after conjugation with CMCyD.
Hattori
M
M
Department of Applied Biological Science, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Tokyo 183-8509, Japan. makoto@cc.tuat.ac.jp
Okada
Y
Y
Takahashi
K
K
D000975:Antioxidants / Q000737:chemistry; D002850:Chromatography, Gel; D003505:Cyclodextrins / Q000737:chemistry*; D007782:Lactoglobulins / Q000737:chemistry*; D011487:Protein Conformation
D000975:Antioxidants; D003505:Cyclodextrins; D007782:Lactoglobulins