title: Comparative studies on NADP(+)-linked malic enzyme in the central nervous system of ectothermic and endothermic animals.
abstract: The maximum activity and intracellular distribution of NADP(+)-linked malic enzyme in brain of Mammalia, Aves, Reptilia, Amphibia and Pisces are reported. Malic enzyme activity was present in all animals brains investigated. Most of the enzyme activity was located in the mitochondrial fraction. In brain of endothermic animals the activity of malic enzyme was several-fold higher than in ectothermic animals. Other NADPH-producing enzymes (i.e. NADP(+)-linked isocitrate dehydrogenase and hexosemonophosphate shunt dehydrogenase) activities were essentially similar in all animals brains tested. However, the total potential capability of NADPH production was lower in ectothermic animals (due mainly to lower malic enzyme activity). It is suggested that the presence of NADP(+)-linked malic enzyme in the brain may be related mainly to mitochondrial metabolism, especially to maintain the mitochondrial pool of NADP+ in reduced form.
authors.affiliation: Department of Biochemistry, Academic Medical School, Gdańsk, Poland.
authors.forename: Z
authors.initials: Z
authors.lastname: Kochan
authors.forename: J
authors.initials: J
authors.lastname: Karbowska
authors.forename: G
authors.initials: G
authors.lastname: Bukato
authors.forename: J
authors.initials: J
authors.lastname: Swierczyński
mesh_terms: D000818:Animals; D001833:Body Temperature Regulation / Q000502:physiology*; D001921:Brain / Q000201:enzymology*; D005954:Glucosephosphate Dehydrogenase / Q000032:analysis; D006801:Humans; D007521:Isocitrate Dehydrogenase / Q000032:analysis; D008291:Malate Dehydrogenase / Q000032:analysis*; D008928:Mitochondria / Q000201:enzymology; D009249:NADP / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000032:analysis*; D010734:Phosphogluconate Dehydrogenase / Q000032:analysis; D013045:Species Specificity; D014714:Vertebrates / Q000502:physiology
chemical_list: D009419:Nerve Tissue Proteins; D009249:NADP; D008291:Malate Dehydrogenase; C030574:malate dehydrogenase (decarboxylating); D007521:Isocitrate Dehydrogenase; D010734:Phosphogluconate Dehydrogenase; C029757:phosphogluconate dehydrogenase (decarboxylating); D005954:Glucosephosphate Dehydrogenase