Abstract
A reliable method for determination of the homocitrullin (N-carbamyl lysine) residue in plasma proteins is presented. The principle of this method is based on the nitrosylation of N-carbamyl group by nitrite in acidic solution, and degradation of nitrosourea to cyanate ion in alkali solution. The liberated cyanate ion is determined by a cyanate ion analyzer. The standard protein sample for determination of the homocitrullin residue was prepared using cyanate-treated bovine serum albumin (BSA). The standardization method was as follows: after hydrolysis in acidic solution, homocitrullin in hydrolysate was determined against standard homocitrullin by the present method. Under physiological conditions, cyanate ion preferentially reacts with ε-amino group in plasma proteins.
