A Simultaneous Estimation Method of DNA and RNA by the Orcinol Reaction and a Study on the Reaction Mechanism

Abstract

The color reaction of orcinol reagent for DNA^* has been investigated. DNA reacted with the orcinol reagent much faster than RNA, and a color with an absorption maximum at 600 mμ was developed within a few minutes. The color intensity at 600 mμ became the maximum in 2 min after the reaction. The maximum of the absorption spectrum of the color developed in the early stage gradually shifted to 665 mμ. The reaction in the early stage was found to take place by the 2-deoxy-D-ribose in DNA molecules, and the color intensity was proportional to the amount of DNA. The ratio of $E665mμ,15mml:minDNAtoE600mμ,2mml:minDNA$ 2 min was constant. This constancy provides a simple method for an evaluation of purity of DNA preparations and it is applicable to the simultaneous estimation of DNA and RNA in the mixture of them. The mechanism of DNA-orcinol reaction is discussed.