Specific interaction of cytosolic and mitochondrial glyoxalase II with acidic phospholipids in form of liposomes results in the inhibition of the cytosolic enzyme only

Abstract

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. Proteins 2000;41:33–39. © 2000 Wiley‐Liss, Inc.

Label-free electronic probing of nucleic acids and proteins at the nanoscale using the nanoneedle biosensor

“…Applications include the study of virology, [1][2][3] ligand fishing, 4,5 bacteriology, 6-8 apoptosis, 9 cell biology and adhesion, 10,11 epitope mapping, [12][13][14] signal transduction, 15,16 immune regulation, 17 nucleic acid-nucleic acid interactions, [18][19][20] and nucleic acid-protein protein interactions, 21,22 and study of post-translational modifications. 23,24 Detection of proteins and nucleic acids is often performed using optical fluorescence based techniques, which are more costly and timely than electrical detection due to the need for expensive and bulky optical equipment and the process of fluorescent tagging. Thus, a robust label-free electrical detection technique can provide for a promising solution in lowering both reagent costs and instrumentation costs.…”

The Human Hydroxyacylglutathione Hydrolase (HAGH) Gene Encodes Both Cytosolic and Mitochondrial Forms of Glyoxalase II

“…In plants and yeast both cytosolic and mitochondrial glyoxalase II play complementary roles in protection against the toxic effects of MG (6,14). It is possible that the mitochondrial enzyme hydrolyzes S-D-lactoylglutathione that has diffused or been transported into the mitochondrial matrix from the cytosol (12). It has also been suggested that uptake of S-D-lactoylglutathione is a possible pathway for the mitochondrial import of GSH (12), although direct import of GSH also occurs (32).…”

“…It is possible that the mitochondrial enzyme hydrolyzes S-D-lactoylglutathione that has diffused or been transported into the mitochondrial matrix from the cytosol (12). It has also been suggested that uptake of S-D-lactoylglutathione is a possible pathway for the mitochondrial import of GSH (12), although direct import of GSH also occurs (32). Alternatively mitochondrial glyoxalase II activity may be required to hydrolyze thiol esters of glutathione formed by non-enzymatic or enzymatic acyl transfer from mitochondrial thiol esters of coenzyme A (9).…”

“…The function of the mitochondrial pool of glyoxalase II activity is unknown. Of interest, glyoxalase I appears to be absent from mitochondria in the rat (9,11), however, S-D-lactoylglutathione has been detected in the mitochondria (12) and so may ultimately provide a substrate for glyoxalase II.…”

Novel U-shape gold nanoparticles-modified optical fiber for localized plasmon resonance chemical sensing

“…A number of label-free detection techniques have been proposed by researchers. Optical biosensors such as surface plasmon resonance, planar waveguides and resonant mirrors are adopted in a wide range of disciplines in the life sciences (Bernard and Lengeler 1978;Bier et al 1997;Jensen et al 1997;Hart et al 1999;Elliott et al 2000;Guermazi et al 2000;Jokiranta et al 2000;Scire et al 2000;Steinrucke et al 2000;Uegaki et al 2000;Xing et al 2000;Wilson 2002). Microcantilever biosensors are reported as a label-free detection technique.…”