A simple and sensitive assay procedure for ribonucleotide reductase system

A sensitive, rapid, and accurate assay for measuring ribonucleotide reductase activity, including the reduction of CDP, UDP, GDP, and ADP to their corresponding deoxyribonucleotides, is described. Using polyethyleneimine-cellulose thin-layer chromatography, I was able to separate the substrates, the reaction products, and the associated hydrolytic products from each other. This procedure allowed me to measure all of the products formed without dephosphorylation or acid hydrolysis. It has been adapted to study the ribonucleotide reductase system of bacteriophage T4-infected cells.