Changes in Activity of Mitochondrial Enzymes during the Development of Xenopus laevis:...

Changes in activity of mitochondrial enzymes were studied during the embryonic development of Xenopus laevis. The following enzymes were determined: malate dehydrogenase (MDH), isocitrate dehydrogenase (NAD+ -dependent) (IDH), aspartate aminotransferase (GOT), cytochrome oxidase (COX), succinate dehydrogenase (SDH), rotenone-insensitive NADH cytochrome c reductase (NADH-red) and monoamine oxidase (MAO). IDH is constant throughout the period studied. COX and SDH, two enzymes of the inner membrane, are constant in pregastrula stages, and subsequently decrease significantly. MDH and NADH-red are highly active in the pregastrula stages and decline thereafter, while MAO is undetectable during early development and increases significantly only in the larvae. GOT increases during the cleavage stages, being most active in the gastrula stages, and decreases subsequently. The results are discussed in the sense of mitochondrial differentiation during the early development of the amphibian embryo.