title: Transport and metabolism of D-lactate in Jerusalem artichoke mitochondria.
abstract: We report here initial studies on D-lactate metabolism in Jerusalem artichoke. It was found that: 1) D-lactate can be synthesized by Jerusalem artichoke by virtue of the presence of glyoxalase II, the activity of which was measured photometrically in both isolated Jerusalem artichoke mitochondria and cytosolic fraction after the addition of S-D-lactoyl-glutathione. 2) Externally added D-lactate caused oxygen consumption by mitochondria, mitochondrial membrane potential increase and proton release, in processes that were insensitive to rotenone, but inhibited by both antimycin A and cyanide. 3) D-lactate was metabolized inside mitochondria by a flavoprotein, a putative D-lactate dehydrogenase, the activity of which could be measured photometrically in mitochondria treated with Triton X-100. 4) Jerusalem artichoke mitochondria can take up externally added D-lactate by means of a D-lactate/H(+) symporter investigated by measuring the rate of reduction of endogenous flavins. The action of the d-lactate translocator and of the mitochondrial D-lactate dehydrogenase could be responsible for the subsequent metabolism of d-lactate formed from methylglyoxal in the cytosol of Jerusalem artichoke.
authors.affiliation: Istituto di Biomembrane e Bioenergetica, CNR, Via G. Amendola 165/A 70126, Bari, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Atlante
authors.forename: Lidia
authors.initials: L
authors.lastname: de Bari
authors.forename: Daniela
authors.initials: D
authors.lastname: Valenti
authors.forename: Roberto
authors.initials: R
authors.lastname: Pizzuto
authors.forename: Gianluca
authors.initials: G
authors.lastname: Paventi
authors.forename: Salvatore
authors.initials: S
authors.lastname: Passarella
mesh_terms: D001692:Biological Transport; D003600:Cytosol / Q000201:enzymology; D006368:Helianthus / Q000166:cytology / Q000378:metabolism*; D045022:Lactate Dehydrogenases / Q000378:metabolism; D019344:Lactic Acid / Q000378:metabolism*; D008928:Mitochondria / Q000201:enzymology / Q000378:metabolism; D010101:Oxygen Consumption; D018517:Plant Roots / Q000166:cytology / Q000201:enzymology; D011765:Pyruvaldehyde / Q000378:metabolism; D013237:Stereoisomerism; D027981:Symporters / Q000378:metabolism; D013869:Thiolester Hydrolases / Q000378:metabolism; D000099301:Hydroxyacylglutathione Hydrolase
chemical_list: D045022:Lactate Dehydrogenases; D019344:Lactic Acid; D011765:Pyruvaldehyde; D027981:Symporters; D013869:Thiolester Hydrolases; D000099301:Hydroxyacylglutathione Hydrolase; C071195:D-lactate dehydrogenase