Two bovine P-lactoglobulin-carboxymethyl dextran (P-LG-CMD) conjugates (conjugates 10A and 10B) were prepared to improve the protein function by using water-soluble carbodiimide. The molar ratios ofP-LG to CMD in the conjugates (Conj) were 7:2 (Conj 10A) and 1:l (Conj 10B). The isoelectric point of each conjugate was 4.7-4.8, which is lower than that of P-LG. Spectroscopic studies suggested that the conformation around had not changed in either conjugate but the a-helix content of Conj 10A had markedly decreased as compared with that of P-LG. Structural analyses with monoclonal antibodies indicated the conformational change of 125Thr-135Lys (a-helix) in Conj 10A and of 15Val-29Ile (P-sheet) in Conj 10B. The denaturation temperature of each conjugate was about 89 "C, which is much higher than that of native P-LG. Each conjugate maintained retinol binding activity as strong as that of native P-LG. The emulsifying activity of P-LG a t neutral pH was much improved by conjugation with CMD.

Depth filters are considered the source of (1-->3)-beta-D-glucan content in some blood components.