Use of a fluorescent DNA analog for fluorometric detection of DNase activity.

The enhancement of fluorescence of the DNA analog poly(d epsilon A) following nucleolytic degradation to mononucleotides was found to be a convenient signal for studying nuclease, especially exonuclease, activity. This measurement, which is simple to obtain and extremely sensitive, detects various kinds of DNases and can be applied to the detection of nucleases in the course of protein purification. The signal change can be observed continuously during the reaction and easily converted to the amount of liberated mononucleotide. The method is thus suitable for quantitative and kinetic studies of exonuclease activity.