Studies of a Mutation Affecting Pyrimidine Degradation in Inbred Mice

Abstract

Dagg, Coleman, and Fraser (Genetics, 49, 979 (1964)) first described a mutation in C57B1/6 mice that resulted in a 3-fold decrease in the capacity of the intact animal, or liver homogenates, to degrade uracil to ,8-alanine, COZ, and ammonia when compared to Rf/J mice.We have examined the mechanism for this metabolic defect by assaying separately the three enzymes involved in pyrimidine degradation in mouse liver in mouse strain Rf/up, from which Rf/J was derived.The three enzymes, dihydrouracil dehydrogenase, dihydropyrimidinase, and fi-ureidopropionase,