Succinic dehydrogenase and cytochrome oxidase of mitochondria of chick liver, heart, and skeletal muscle during embryonic development

✍ Scribed by Greenfield, Phyllis C. ;Boell, E. J.

• Publisher: John Wiley and Sons
• Year: 1968
• Tongue: English
• Weight: 831 KB
• Volume: 168
• Category: Article
• ISSN: 0022-104X
• DOI: 10.1002/jez.1401680409

✦ Synopsis

The specific activities of succinic dehydrogenase (SD) and cytochrome oxidase (COX) were determined for mitochondria of chick liver, heart, and skeletal muscle from the seventh day of incubation through the time of hatching. The levels of activity of both enzymes at hatching and the rate and course of the developmental changes by which the final levels are reached are different and specific for mitochondria of the three tissues studied. During development changes in activity of both enzymes occur in parallel so that the ratio of SD/COX remains constant. Furthermore, the ratio is the same for the three types of mitochondria. Cytochrome oxidase is completely localized in the insoluble protein fraction (membrane fraction) of all mitochondria examined, and the change in COX during development varies temporally and quantitatively with the proportion of insoluble protein. When calculated on the basis of insoluble protein, specific activities of SD and COX are constant throughout development; furthermore, differences in activity among the mitochondria of the three tissues disappear. It is conchded that mitochondrial differentiation reflects the appearance of specific proportions of membranes and matrix.