Mitochondrial enzymes in mango fruit during ripening.
Baqui S. M., Mattoo A. K., Modi V. V.
Author Affiliation: Maharaja Sayajirao University of Baroda, India.
Phytochemistry 13 : 2049-2055
Abstract : Mitochondria isolated from immature (developing), mature (unripe), and ripe mango pulp actively oxidized the intermediates of the Krebs cycle. The oxidation of citrate, oxoglutarate, succinate and malate by both unripe and ripe fruit mitochondria was several-fold greater than that in immature fruit. The levels of malic dehydrogenase and succinic dehydrogenase increased with the onset of ripening, whereas the level of citrate synthase increased several-fold on maturation but decreased 6-fold on ripening. Isocitrate dehydrogenase and malic enzyme activities were very high in the immature fruit but after a sudden decrease in the matured fruit showed a considerable rise thereafter. The ratio of the activities of isocitrate lyase to isocitrate dehydrogenase was considerably higher in immature than ripe fruit and greatest in mature fruit. This, together with a higher concentration of glyoxylate at these stages indicated the operation of the glyoxylate by-pass. Oxidized and reduced forms of pyridine nucleotides were estimated.