Enzymatic studies of radiation damage

Progress is reported on studies related to molecular mechanisms for radiation damage to cells. Mung bean nuclease was shown to excise the A + T rich regions from different species of DNA exposed to premelting temperatures. This suggests an additional application of mung bean nuclease as a means of detection of slightly damaged reglons of DNA. A new sensitive method for the determination of nucleoside monophosphates and nucleoside 3', 5'-diphosphates was developed. The method was applied to the determination of the frequency of nucleosides appearing in the terminal position of an oligonucleotide. An argument serves biological unity of all nucaeases is presented. (auth