NADH-DIAPHORASE ACTIVITY IN SUBCELLULAR FRACTIONS OF MOUSE TISSUES

Subcellular fractions were obtained from the liver, kidney, heart and femoral muscles, and the small intestinal mucosa of mice according to Strittmatter et al. and the distribution of NADH-diaphorase activity and the specific activity of the enzyme were examined.1. The method was suitable for fractionating the liver and kidney tissues, but the microsomal fractions of the heart and femoral muscles and small intestinal mucosa were contaminated with mitochondria.2. Distribution of the NADH-diaphorase activity in the subcellular fractions was corrected for the contamination of mitochondria. It was found that the liver, kidney, and small intestinal mucosa contained the enzyme activity both in mitochondria and microsomes whereas the heart and femoral muscles contained mainly in mitochondria.3. In the liver, kidney, heart and femoral muscle, the specific activity of the NADH-diaphorase was higher in mitochondria than in microsomes, whereas it was higher in microsomes than in mitochondria in the small intestinal mucosa.4. The NADH-diaphorase activity in small intestinal mucosa was as a whole lower than that in liver and kidney, but relatively higher in microsomes than in mitochondria. It was taken as a favorable support of the assumption of the authors that the NADH-diaphorase activity of microsomes was involved in cell proliferation.