Determination of nucleic acids at nanogram levels by their enhancement effect on the rate of the metalloporphyrin-catalyzed p-hydroxyphenylacetic acid fluorescence reaction

Abstract

Nucleic acids were determined on the basis of the finding that the catalytic activity of iron(III) tetrakis(o-aminophenyl)porphyrin (Fe(III)(o-NH2)TPP), a mimetic peroxidase, in the fluorogenic reaction between p-hydroxyphenylacetic acid (p-HPA) and H2O2 is significantly enhanced in the presence of DNA (or RNA). The degree of fluorescence enhancement is a measure of the nucleic acid concentration. Under optimum conditions, the calibration curves for the determination of calf thymus (CT DNA) and yeast RNA were linear over the ranges 0-200.0 ng mL(-1). he corresponding detection limits are 0.8 ng mL(-1) for CT DNA and 1.1 ng mL(-1) for yeast RNA, respectively. The relative standard deviation of seven replicate measurements is 2.2% for 100 ng mL(-1) CT DNA. Interferences from some interesting co-existing substances in the determination of DNA were also examined. The potential application of the method was also further proved by the determination of DNA in golden staphylococcus DNA sample.