Oxidoreductases and hydrolases as marker enzymes for ultracentrifugation of islets of Langerhans of rats.

Using quantitative fluorometric micro methods the presence of glutamate dehydrogenase, acid galactosidase, and acid glucuronidase was detected in pancreatic islets of the rat. Some properties of these enzymes and of malate dehydrogenase, 6-phosphogluconate dehydrogenase, and acid phosphatase were investigated. It has been shown that subcellular fractions of homogenates of islets of Langerhans can be characterized by using glutamate dehydrogenase, 6-phosphogluconate dehydrogenase, and acid hydrolases as marker enzymes for mitochondria, cytosol, and lysosomes, respectively. The degree of contamination from acinar tissue in the islet preparations was calculated from the amylase activity of the homogenates.