Submitochondrial location and some properties of NAD+- and NADP+-linked malate dehydrogenase in Euglena.

Abstract

NAD+-linked malate dehydrogenase [L-malate: NAD+ oxidoreductase, EC 1.1.1.37](NAD+-MDH) is distributed in mitochondria, microbodies and cytosol of most organisms,1 ~4) while the NADP+-linked enzyme [L-malate: NADP+ oxidoreductase, EC 1.1.1.82](NADP+-MDH) is found only in chloroplasts of higher plants.5>6)In Euglena, the occurrence, subcellular location and properties of NAD+-MDHhave been reported,1 ~3) but no information is available on NADP+-MDH in this protozoan.In the present paper are reported the occurrence, submitochondrial location and some properties of NAD+-and NADP+-MDHin Euglena gracilis.E. gracilis SM-ZK, a streptomycin-bleached strain, was cultured for 5 days at 27°C under illumination (2,000lux) in the Oda medium.7)The activity of NADP+-MDH was assayed in 2ml of reaction mixture containing 50mM