Identification of the binding site of methylglyoxal on glutathione peroxidase: methylglyoxal inhibits glutathione peroxidase activity via binding to glutathione binding sites Arg 184 and 185.
Methylglyoxal (MG), a physiological alpha-dicarbonyl compound is derived from glycolytic intermediates and produced during the Maillard reaction. The Maillard reaction, a non-enzymatic reaction of ketones and aldehydes with amino group of proteins, contributes to the aging of proteins and to complications associated with diabetes. In our previous studies (Che, et al. (1997) "Selective induction of heparin-binding epidermal growth factor-like growth factor by MG and 3-deoxyglucosone in rat aortic smooth muscle cells. The involvement of reactive oxygen species formation and a possible implication for atherogenesis in diabetes". J. Biol. Chem., 272, 18453-18459), we reported that MG elevates intracellular peroxide levels, but the mechanisms for this remain unclear. Here, we report that MG inactivates bovine glutathione peroxidase (GPx), a major antioxidant enzyme, in a dose- and time-dependent manner. The use of BIAM labeling, it was showed that the selenocysteine residue in the active site was intact when GPx was incubated with MG. MALDI-TOF-MS (matrix-assisted laser desorption/ionization time-of-flight mass spectrometry) and protein sequencing examined the possibility that MG modifies arginine residues in GPx. The results show that Arg 184 and Arg 185, located in the glutathione binding site of GPx was irreversively modified by treatment with MG. Reactive dicarbonyl compounds such as 3-deoxyglucosone, glyoxal and phenylglyoxal also inactivated GPx, although the rates for this inactivation varied widely. These data suggest that dicarbonyl compounds are able to directly inactivate GPx, resulting in an increase in intracellular peroxides which are responsible for oxidative cellular damage.
Park
Yong Seek
YS
Department of Biochemistry, Osaka University Medical School, Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
Koh
Young Ho
YH
Takahashi
Motoko
M
Miyamoto
Yasuhide
Y
Suzuki
Keiichiro
K
Dohmae
Naoshi
N
Takio
Koji
K
Honke
Koichi
K
Taniguchi
Naoyuki
N
D000595:Amino Acid Sequence; D000818:Animals; D001120:Arginine / Q000737:chemistry*; D001665:Binding Sites; D002417:Cattle; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D003847:Deoxyglucose / Q000031:analogs & derivatives* / Q000737:chemistry; D004912:Erythrocytes / Q000378:metabolism; D005978:Glutathione / Q000737:chemistry; D005979:Glutathione Peroxidase / Q000737:chemistry* / Q000378:metabolism; D006037:Glyoxal / Q000737:chemistry; D013058:Mass Spectrometry; D008666:Metalloendopeptidases / Q000494:pharmacology; D008969:Molecular Sequence Data; D009130:Muscle, Smooth / Q000166:cytology; D018384:Oxidative Stress; D010455:Peptides / Q000737:chemistry; D010658:Phenylglyoxal / Q000737:chemistry; D011485:Protein Binding; D011765:Pyruvaldehyde / Q000737:chemistry / Q000494:pharmacology*; D051381:Rats; D017279:Selenocysteine / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013997:Time Factors
D010455:Peptides; D017279:Selenocysteine; D006037:Glyoxal; D011765:Pyruvaldehyde; D001120:Arginine; D003847:Deoxyglucose; D005979:Glutathione Peroxidase; D008666:Metalloendopeptidases; C039830:peptidyl-Lys metalloendopeptidase; C016350:3-deoxyglucosone; D005978:Glutathione; D010658:Phenylglyoxal