The action of iodine on deoxyribonucleic acid

Abstract

Treatment of deoxyribonucleic acid with iodine at pH 5·3 at 98–100° for 5 minutes oxidised the cytosine residues much more rapidly than the thymine residues; guanine and adenine residues were unaffected. Urea was liberated from the oxidised deoxyribonucleic acid on hydrolysis with N-alkali at 100° for 1 hr. Treatment of the oxidised product with a solution of 2% diphenylamine in 66·7% formic acid at 37° for 60 hr. gave thymine-containing oligonucleotides and small amounts of oligonucleotides containing both cytosine and thymine. Thymidine-3′,5′-diphosphate and bisthymidinetriphosphate were isolated and characterised.