Collect. Czech. Chem. Commun. 1983, 48, 662-667

Stability of dicyclohexylcarbodiimide in an aqueous medium. The effect of mitochondrial phospholipids

Jan Kopeckýa, Stanislav Pavelkaa, Jiří Dědinaa, Věra Siglerováb and Karel Verešb

a Institute of Physiology
b Institute of Radiochemistry, Czechoslovak Academy of Sciences, 142 20 Prague 4


The stability of N,N'-dicyclohexylcarbodiimide (DCCD) was analyzed with respect to the use of DCCD as a specific chemical modifier of membrane-bound enzymes. The disappearance of DCCD from the sucrose-Tris medium obeyes the pseudo-first-order kinetics the rate constant (kd) of which is pH-dependent (kd = 12.0 . 10-3 min-1 at pH 6.0, and kd = 1.6 . 10-3 min-1 at pH 9.0, respectively). However, the rate of the total [14C]DCCD binding to mitochondrial membrane proteins is not markedly influenced by the change of pH (6.0-9.0). The rate of DCCD disappearance is enhanced in the presence of mitochondrial phospholipids. It is concluded that the rapid equilibration of DCCD between the phospholipid and water phase, the reactivity of DCCD with phospholipids, H+-stimulated hydration of DCCD to dicyclohexylurea and the sorption of DCCD to the test tube must be considered when studying the interaction of DCCD with membrane-bound enzymes.