Binding of lambda carrageenan to bovine serum albumin and non-equilibrium effects of complexation

Binding of lambda carrageenan (lCG) to bovine serum albumin (BSA) and the effect formation path, namely mixing (M) at specific pH versus titration (T) from a neutral mixture, on complexation have been studied using turbidimetry, phase analysis, dynamic light scattering, confocal laser scanning bright-field optical microscopy, circular dichroism fluorescence measurements. The sizes shape complex particles formed under T-conditions differ significantly those obtained M-conditions, maximal T-complexes contain less lCG as compared M-complexes. At below pIBSA analysis reveals two domains q corresponding an approximately constant lCG/BSA weight ratio in q* (domain I), decreasing II). stoichiometries 4.2 4.7 are 1:77 1:119 mole lCG/mole BSA. yield BSA is higher than 98% 4.7, complexes form stable presence 1.0M–1.5M NaCl. interaction did not lead protein denaturation or significant changes tertiary secondary structure illustrates enhancement hydrophobicity within particles. 5.2 (pH wrong side PIBSA) up 37.6% was bound lCG, (q*) weakly dependent complete range studied. molecular origin unusually strong between discussed.