RESUMO
The effect of melatonin on respiration and production (release) of hydrogen peroxide during succinate oxidation in mitochondria isolated from lupine cotyledons and epicotyls of pea seedlings was studied. It was shown for the first time that melatonin (10-7-10-3 M) had a significant inhibitory effect on the production of peroxide by plant mitochondria, which was characterized by concentration dependence and species specificity. At the same time, melatonin (at a concentration of up to 100 µM) had virtually no effect on mitochondrial respiration rate and respiratory control coefficient. The results confirm the antioxidant function of melatonin and indicate that it is involved in the regulation of ROS levels and maintenance of redox balance in plant mitochondria.
Assuntos
Lupinus/citologia , Melatonina/farmacologia , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Peróxidos/metabolismo , Pisum sativum/citologia , Relação Dose-Resposta a Droga , Lupinus/efeitos dos fármacos , Pisum sativum/efeitos dos fármacos , Ácido Succínico/metabolismoRESUMO
The PepP protein has been purified in vitro and characterized for the first time. It is encoded by the sll0136 gene of the unicellular cyanobacterium Synechocystis sp. PCC6803. It is established that the PepP protein is a Mn2+-dependent Xaa-Pro-specific aminopeptidase. The protein in the reaction of hydrolysis of the fluorescent peptide Lys(N-Abz)-Pro-Pro-pNA has a maximal activity at pH 7.6 and 32°C.