THE PHOTOCHEMICAL REACTIONS OF 1,3–DIMETHYLURACIL WITH 1–AMINOPROPANE AND POLY‐l‐LYSINE*

Irradiation of 1,3–dimethyluracil (DMU) in 1–aminopropane (AP) with u.v. light resulted in the formation of reduced and dimeric forms of DMU and adducts between DMU and AP. The formation of these compounds may be rationalized from the activation of either DMU or AP. Irradiation of DMU and poly‐l‐lysine in water with u.v. light resulted in the extensive binding of DMU to poly‐l‐lysine. The pyrimidine is probably attached to the ε‐carbon of the polypeptide at the 6–position. The biological implications of these studies are discussed.