m. Chloroperbenzoic acid (CPBA) was used as a photosensitizer in the photolysis of human red blood cells. Treatment of the cells with 25, 50 100, or 200 mu M CPBA produced 3.5%, 85.9%, 252.6% or 350.9% photohemolysis, respectively, compared with untreated control cells. Some copper (II) complex [CuL2] with SOD-like activity containing 2-methyl amino pyridine and various anions (Cl-, Br-, NO3-, ClO4-, or SO4--) were tested for their protective efficiency toward the cell damage photoinduced by CPBA. Treatment of the cells with maximum dose (200 mu M) Cu(II), bromide, chloride, nitrate, sulfate, or perchlorate complexes with 2-methyl amino pyridine produced 85.87%, 59.28%, 49.29%, 33.47%, or 23.80% protection, respectively, against the cells irradiated without addition of Cu(II) complexes. A mechanism involving oxygen radicals and sensitizer photodegradation products was suggested to interpret the results. (C) 1997 Elsevier Science Inc.