A cytochemical study of the dehydrogenases of mitochondria and mitochondrial particulates by a monotetrazolium-cobalt chelation method

In one of the current histochemical methods for dehydrogenases and diaphorases the final product is a metal-formazan dye derived from reduction of an N-thiazolyl-substituted tetrazolium. Sites of enzymic activity consistently appear as intramitochondrial dots 0.2 to 0.3 µ in diameter. When applied to active particles from disrupted mitochondria (Keilin-Hartree preparation, electron transport particle, Cooper-Lehninger particle) the individual particles appear as black dots 0.1 to 0.3 µ in diameter. It is clear that formazan is deposited progressively upon the particles and the results suggest that the latter may be spatially arranged in mitochondria so that areas of activity are separated by quiescent regions.

Dehydrogenases of neurospora crassa

Malate, isocitrate, glucose-6-phosphate, and 6-phosphogluconate dehydrogenases of the homogenate prepared from the mycelia of several wild strains of Neurospora crassa have been subjected to zone electrophoresis in starch gel. Four electrophoretically different malate dehydrogenases, a single isocitrate dehydrogenase, three glucose-6-phosphate dehydrogenases, and two 6-phosphogluconate dehydrogenases were obtained regardless of the strain or the media in which the organism was grown.