On the presence and significance of coenzyme Q in microsomes

Mitochondrial and microsomal fractions were prepared from rat liver and particularly from porcine adrenal glands. However, microsomal fractions which are completely free from mitochondrial fragments are very difficult to obtain. Since the succinoxidase enzyme system occurs only in mitochondria, it was possible to determine the percentage of mitochondrial contamination in the microsomal preparations. Such data are necessary in order to estimate the coenzyme Q content of microsomes. Coenzyme Q 10 was found in microsomes from porcine adrenal glands, and both Q 9 and Q 10 were found in the microsomes of rat liver. It appears, therefore, that the coenzyme is implicated in enzyme systems of microsomes as well as those of mitochondria. Further research on adrenal mitochondrial and microsomal enzymic reactions in which coenzyme Q participates may be particularly merited.