The use of Mn-TPPS4 mimetic peroxidase in a DNA hybridization assay

We report here a new detection method for lambda DNA on a luminescent tube of a LKB-1251 Luminometer. The process utilizes transaminated lambda DNA labeled with biotin (Bio) as probe; avidin was used as a bridge to link the hybrids and Bio-BSA-Mn-TPPS4. Mn-TPPS4 [Mn-tetrakis(sulfophenyl)porphyrin] in the conjugate acted as a mimetic peroxidase of horseradish peroxidase, which can catalyze the chemiluminescence reaction between luminol and hydrogen peroxide. The factors affecting the detection capacity were the molar ratio of Mn-TPPS4 to BSA, biotin to lambda DNA, biotin to BSA-Mn-TPPS4, and the concentration of the probe, avidin, and Bio-BSA-Mn-TPPS4. The chemiluminescence intensity produced by the reaction between luminol and hydrogen peroxide, catalyzed by Mn-TPPS4 in Bio-BSA-Mn-TPPS4, is proportional to the amount of target DNA; 10-400 pg/tube of DNA can be determined with a detection limit of 4 pg/tube (S/N = 2.5). (C) 1995 Academic Press. Inc.