Chemical Biology of Homocysteine Thiolactone and Related Metabolites
Section snippets
Abstract
Protein-related homocysteine (Hcy) metabolism produces Hcy-thiolactone, N-Hcy-protein, and Nε-homocysteinyl-lysine (Nε-Hcy-Lys). Hcy-thiolactone is generated in an error-editing reaction in protein biosynthesis when Hcy is erroneously selected in place of methionine by methionyl-tRNA synthetase. Hcy-thiolactone, an intramolecular thioester, is chemically reactive and forms isopeptide bonds with protein lysine residues in a process called N-homocysteinylation, which impairs or alters the
Chemical Synthesis
Hcy-thiolactone can be easily prepared from Met or Hcy. The hydriodic acid digestion procedure, originally developed by Bearnstein for the determination of protein Met content [2], allows quantitative conversion of Met to Hcy-thiolactone with the liberation of methyl iodide. The hydriodic acid digestion of [35S]Met is a convenient method for the preparation of [35S]Hcy-thiolactone for biological studies [5], [6], [7], [12], [32], [33], [34], [35], [36], [37]. Recent studies have shown that the
Synthesis In Vitro
Because the high energy of the anhydride bond of ATP is conserved in the thioester bond of Hcy-thiolactone, it is chemically reactive and easily acylates amino groups in proteins and free-amino acids in vitro forming N-Hcy-protein [5], [6], [7], [27] (Fig. 1). N-Hcy-proteins are easily prepared in vitro by incubating desired protein with Hcy-thiolactone at pH 7.4. The reaction is completed in 4 h at 37 °C or 40 h at 25 °C. When human plasma is incubated with Hcy-thiolactone, each protein becomes N
Chemical Synthesis
The isopeptide Nε-Hcy-Lys (Fig. 1) has been originally identified in vitro as a product of facile reaction of Hcy-thiolactone with lysine [6], [27]. Nε-Hcy-Lys is synthesized in solution phase using common procedures for peptide synthesis starting from commercially available lysine derivative (ε-N-Cbz-Lys-O-Bu) [71]. Nε-Hcy-Lys isopeptide is also synthesized by incubating 5 mmol of l-lysine and 5 mmol of d,l-Hcy-thiolactone hydrochloride [9] in 100 ml 0.2 M sodium phosphate buffer, pH 7.4, 0.2
Conclusions
As outlined above, protein-related Hcy metabolism generates Hcy-thiolactone, N-Hcy-protein, and Nε-Hcy-Lys. Hcy-thiolactone affects biological function due to its ability to modify protein lysine residues in the process called N-homocysteinylation. N-Homocysteinylation causes protein damage, which is further exacerbated by a thiyl radical-mediated oxidation. N-Hcy-proteins undergo structural changes leading to aggregation and amyloid formation. These structural changes generate proteins, which
References (92)
- et al.
The formation of homologue of cysteine by the decomposition of methionine with sulfuric acid
J. Biol. Chem.
(1932) A modification of the method for determining methionine in proteins
J. Biol. Chem.
(1934)Metabolism of homocysteine thiolactone in human cell cultures: possible mechanism for pathological consequences of elevated homocysteine levels
J. Biol. Chem.
(1997)Translational accuracy of aminoacyl-tRNA synthetases: implications for atherosclerosis
J. Nutr.
(2001)Translational incorporation of S-nitroso-homocysteine into protein
J. Biol. Chem.
(2000)Mechanisms of homocysteine-induced atherothrombosis
J. Thromb. Haemost.
(2005)Pathophysiological consequences of homocysteine excess
J. Nutr.
(2006)Homocysteine thiolactone: metabolic origin and protein homocysteinylation in humans
J. Nutr.
(2000)Protein N-homocysteinylation: implications for atherosclerosis
Biomed. Pharmacother.
(2001)Calcium-dependent human serum homocysteine thiolactone hydrolase: a protective mechanism against protein-N-homocysteinylation
J. Biol. Chem.
(2000)
Genetic determinants of homocysteine thiolactonase activity in humans: implications for atherosclerosis
FEBS Lett.
Cross-talk between Cys34 and lysine residues in human serum albumin revealed by N-homocysteinylation
J. Biol. Chem.
Protective mechanisms against homocysteine toxicity: the role of bleomycin hydrolase
J. Biol. Chem.
Facile syntheses of [35S] homocysteine-thiolactone, [35S] homocysteine, [35S] homocysteine, and [S-nitroso-35S] homocysteine
Anal. Biochem.
The isolation of homocysteine and its conversion to a thiolactone
J. Biol. Chem.
The determination of homocysteine thiolactone in biological samples
Anal. Biochem.
The determination of homocysteine–thiolactone in human plasma
Anal. Biochem.
Opening the ring of the thiolactone of homocysteine
J. Biol. Chem.
Preparation of L-homocysteine from L-homocysteine thiolactone
Anal. Biochem.
Proofreading in vivo: editing of homocysteine by aminoacyl-tRNA synthetases in Escherichia coli
J. Biol. Chem.
Metabolism of homocysteine-thiolactone in plants
J. Biol. Chem.
Determination of homocysteine thiolactone and homocysteine in cell cultures using high-performance liquid chromatography with fluorescence detection
J. Chromatogr. B
Direct monitoring of albumin lysine-525 N-homocysteinylation in human serum by liquid chromatography/mass spectrometry
Anal. Biochem.
Effect of homocysteinylation on high density lipoprotein physico-chemical properties
Chem. Phys. Lipids
Protein N-homocysteinylation induces the formation of toxic amyloid-like protofibrils
J. Mol. Biol.
Aging and oxidation of reactive protein sulfhydryls
Exp. Gerontol.
Age related changes in oxidized proteins
J. Biol. Chem.
Protein oxidation in aging, disease, and oxidative stress
J. Biol. Chem.
Homocysteine is a protein amino acid in humans: implications for homocysteine-linked disease
J. Biol. Chem.
New method for the determination of protein N-linked homocysteine
Anal. Biochem.
Increased plasma protein homocysteinylation in hemodialysis patients
Kidney Int.
Plasma homocysteine thiolactone adducts associated with risk of coronary heart disease
Clin. Chim. Acta
Immunohistochemical detection of N-homocysteinylated proteins in humans and mice
Biomed. Pharmacother.
Fully automated method for simultaneous determination of cysteine, cysteinylglycine, glutathione and homocysteine in plasma by high performance liquid chromatography
J. Chromatogr. B
Pathways and regulation of homocysteine metabolism in mammals
Semin. Thromb. Hemost.
Synthesis of homocysteine thiolactone by methionyl-tRNA synthetase in cultured mammalian cells
FEBS Lett.
Homocysteine thiolactone and protein homocysteinylation in human endothelial cells: implications for atherosclerosis
Circ. Res.
Protein homocysteinylation: possible mechanism underlying pathological consequences of elevated homocysteine levels
FASEB J.
Mutations in cystathionine beta-synthase or methylenetetrahydrofolate reductase gene increase N-homocysteinylated protein levels in humans
FASEB J.
Identification and origin of Nε-homocysteinyllysine isopeptide in humans and mice
Amino Acids
Elevated levels of N-Hcy-Lysine isopeptide in acute myocardial infarction: links with ADMA formation
Clin. Chem. Lab. Med.
Disorders of transsulfuration
Inherited disorders of folate and cobalamin transport and metabolism
Homocysteine-lowering by B vitamins slows the rate of accelerated brain atrophy in mild cognitive impairment: a randomized controlled trial
PLoS ONE
Neural-tube defects and derangement of homocysteine metabolism
N. Engl. J. Med.
Homocysteine and folate in pregnancy
Clin. Chem.
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