Immunochemical approach to characterize post-translational modification of serum albumin using anti-glutaraldehyde-treated serum albumin antibodies.

Polyclonal antibodies against glutaraldehyde-treated rabbit serum albumin (pRSA) and human serum albumin (pHSA) were prepared from rabbit and mouse, respectively. Anti-pRSA antibody had the structural determinant depending on the polymerization process of RSA and showed only a weak cross-reactivity with the other glutaraldehyde-treated albumins. Anti-pHSA antibody (after adsorption of anti-HSA antibody) recognized only pHSA, but not HSA and the other treated albumins. The cross-reactivity of those antibodies was examined with albumins treated by other methods such as modification of glucose and fructose, carbodiimide, and transglutaminase. Among the, RSA and HSA modified with glucose and fructose had an affinity for each antibody and the reactivity depended on the extent of formation of the polymerized albumin. The results suggests that functional groups involved in cross-linking of albumin are important for formation of the cross-reactivity with the antibody and that a definite structure immunochemically similar to glutaraldehyde-treated albumin could be formed by the Maillard reaction.