Abstract
The significant diaphorase activities which could not be explained by contaminating mitochondria and microsomes are consistently present in isolated calf thymus nuclei. The nuclei seemed to contain at least two apparently different diaphorase activities. Most of the NADH-ferricyanide reductase activity was retained in the nuclei purified by sucrose-gradient centrifugation and sonication. Triton treatment which remove cytoplasmic contaminants and the outer layer of nuclear membrane resulted in no decrease of NADH-ferricyanide reductase activity in nuclear preparation.
