Specific interaction of cytosolic and mitochondrial glyoxalase II with acidic phospholipids in form of liposomes results in the inhibition of the cytosolic enzyme only.
Kinetics of cytosolic recombinant human glyoxalase II and bovine liver mitochondrial glyoxalase II were studied in the presence of liposomes made of different phospholipids (PLs). Neutral PLs such as egg phosphatidylcholine or dipalmitoylphosphatidylcholine did not affect the enzymatic activity of either enzymatic form. Liposomes made of dioleoyl phosphatidic acid or cardiolipin or phosphatidylserine also did not affect the enzymatic activity of mitochondrial glyoxalase II. Conversely, these negatively charged PLs exerted noncompetitive inhibition on cytosolic glyoxalase II only, dioleoyl phosphatidic acid and bovine brain phosphatidylserine exerting the highest and lowest inhibition, respectively. Binding studies, carried out by using a resonant mirror biosensor, revealed that liposomes made of negatively charged PLs interact specifically with both enzymatic forms of glyoxalase II, whereas interactions were not detected with neutral PLs. Once bound on glyoxalase II, negatively charged liposomes could not be removed by 3 M NaCl, suggesting that interactions between glyoxalase II and negatively charged PLs, besides ionic, may be also hydrophobic. These data suggest a possible role of negatively charged phospholipids in the regulation of level of lactoylglutathione in the cell. The data are also discussed in terms of a possible regulation of reduced glutathione supply to mitochondria.
Scirè
A
A
Istituto di Biochimica, Facoltà di Medicina e Chirurgia, Università degli Studi di Ancona, Ancona, Italy.
Tanfani
F
F
Saccucci
F
F
Bertoli
E
E
Principato
G
G
D000818:Animals; D002417:Cattle; D003600:Cytosol / Q000201:enzymology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008081:Liposomes; D008928:Mitochondria / Q000201:enzymology*; D010743:Phospholipids / Q000378:metabolism*; D011485:Protein Binding; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D013869:Thiolester Hydrolases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000099301:Hydroxyacylglutathione Hydrolase
D008081:Liposomes; D010743:Phospholipids; D011994:Recombinant Proteins; D013869:Thiolester Hydrolases; D000099301:Hydroxyacylglutathione Hydrolase