| S-Aminoethyl-l-cysteine, also known as thialysine, is a toxic analog of the amino acid lysine in which the second carbon of the amino acid's R-group (side chain) has been replaced with a sulfur atom.
Strictly speaking, L-thialysine is actually considered an S-(2-aminoethyl) analogue of L-cysteine. This compound is known to have cytotoxic affects as it inhibits protein synthesis and lysine 2,3-aminomutase. |
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| InChI=1S/C5H12N2O2S/c6-1-2-10-3-4(7)5(8)9/h4H,1-3,6-7H2,(H,8,9)/t4-/m0/s1 |
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Bronsted base
A molecular entity capable of accepting a hydron from a donor (Bronsted acid).
(via organic amino compound )
Bronsted acid
A molecular entity capable of donating a hydron to an acceptor (Bronsted base).
(via oxoacid )
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protein synthesis inhibitor
A compound, usually an anti-bacterial agent or a toxin, which inhibits the synthesis of a protein.
metabolite
Any intermediate or product resulting from metabolism. The term 'metabolite' subsumes the classes commonly known as primary and secondary metabolites.
EC 5.4.3.2 (lysine 2,3-aminomutase) inhibitor
An EC 5.4.3.* (intramolecular transferase transferring amino groups) inhibitor that interferes with the action of lysine 2,3-aminomutase (EC 5.4.3.2).
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View more via ChEBI Ontology
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S-(2-aminoethyl)-L-cysteine
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(2R)-2-amino-3-(2-aminoethylsulfanyl)propanoic acid
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PDB
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(R)-2-amino-3-(2-aminoethylthio)propanoic acid
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ChEMBL
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2-Aminoethylcysteine
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HMDB
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4-Thia-L-lysine
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HMDB
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4-Thialysine
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HMDB
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Aminoethylcysteine
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ChemIDplus
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gamma-Thia-lys
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ChemIDplus
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gamma-Thialysine
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ChemIDplus
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S-2-Aminoethyl cysteine
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ChemIDplus
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S-beta-Aminoethyl cysteine
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ChemIDplus
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Thiosine
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ChemIDplus
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1006349
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Gmelin Registry Number
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Gmelin
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1705488
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Reaxys Registry Number
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Reaxys
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2936-69-8
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CAS Registry Number
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ChemIDplus
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Tang KH, Mansoorabadi SO, Reed GH, Frey PA (2009)
Radical triplets and suicide inhibition in reactions of 4-thia-D- and 4-thia-L-lysine with lysine 5,6-aminomutase.
Biochemistry 48, 8151-8160 [PubMed:19634897]
[show Abstract]
Lysine 5,6-aminomutase (5,6-LAM) catalyzes the interconversions of D- or L-lysine and the corresponding enantiomers of 2,5-diaminohexanoate, as well as the interconversion of L-beta-lysine and l-3,5-diaminohexanoate. The reactions of 5,6-LAM are 5'-deoxyadenosylcobalamin- and pyridoxal-5'-phosphate (PLP)-dependent. Similar to other 5'-deoxyadenosylcobalamin-dependent enzymes, 5,6-LAM is thought to function by a radical mechanism. No free radicals can be detected by electron paramagnetic resonance (EPR) spectroscopy in reactions of 5,6-LAM with D- or L-lysine or with L-beta-lysine. However, the substrate analogues 4-thia-L-lysine and 4-thia-D-lysine undergo early steps in the mechanism to form two radical species that are readily detected by EPR spectroscopy. Cob(II)alamin and 5'-deoxyadenosine derived from 5'-deoxyadenosylcobalamin are also detected. The radicals are proximal to and spin-coupled with low-spin Co(2+) in cob(II)alamin and appear as radical triplets. The radicals are reversibly formed but do not proceed to stable products, so that 4-thia-D- and L-lysine are suicide inhibitors. Inhibition attains equilibrium between the active Michaelis complex and the inhibited radical triplets. The structure of the transient 4-thia-L-lysine radical is analogous to that of the first substrate-related radical in the putative isomerization mechanism. The second, persistent radical is more stable than the transient species and is assigned as a tautomer, in which a C6(H) of the transient radical is transferred to the carboxaldehyde carbon (C4') of PLP. The persistent radical blocks the active site and inhibits the enzyme, but it decomposes very slowly at | Maity AN, Hsieh CP, Huang MH, Chen YH, Tang KH, Behshad E, Frey PA, Ke SC (2009)
Evidence for conformational movement and radical mechanism in the reaction of 4-thia-L-lysine with lysine 5,6-aminomutase.
The journal of physical chemistry. B 113, 12161-12163 [PubMed:19685884]
[show Abstract]
We demonstrate that the steady state reaction of lysine 5,6-aminomutase with substrate analogue 4-thia-l-lysine generates a radical intermediate, which accumulates in the enzyme to an electron paramagnetic resonance (EPR) detectable level. EPR line width narrowing of approximately 1 mT due to [4'-(2)H] labeling of the pyridoxal-5'-phosphate (PLP), an isotropic hyperfine coupling of 40 MHz for the proton at C4' of PLP derived from (2)H electron nuclear double resonance (ENDOR) measurement, and spin density delocalization onto the (31)P of PLP realized from observations of the (31)P ENDOR signal provide unequivocal identification of the radical as a substrate-PLP-based species. X- and Q-band EPR spectra fittings demonstrate that this radical is spin coupled with the low spin Co(2+) in cob (II) alamin and the distance between the two species is about 10 A. These results provide direct evidence for the active site motion upon substrate binding, bringing the adenosylcobalamin to the proximity of substrate-PLP for subsequent H-atom abstraction and for the notion that lysine 5,6-aminomutase functions by a radical mechanism. Observation of (2)H-ENDOR signal also provides a reliable hyperfine coupling constant for future comparison with quantum-mechanical-based calculations to gain further insight into the molecular structure of this steady state radical intermediate. | Ogo N, Oishi S, Matsuno K, Sawada J, Fujii N, Asai A (2007)
Synthesis and biological evaluation of L-cysteine derivatives as mitotic kinesin Eg5 inhibitors.
Bioorganic & medicinal chemistry letters 17, 3921-3924 (Source: ChEMBL) [PubMed:17524640]
[show Abstract]
Inhibition of Eg5 represents a novel approach for the treatment of cancer. Here, we report the synthesis and structure-activity relationship of S-trityl-L-cysteine (STLC) derivatives as Eg5 inhibitors. Some of these derivatives such as 4f demonstrated enhanced inhibitory activity against Eg5 and induced mitotic arrest with characteristic monoastral spindles in HeLa cells. | Sandala GM, Smith DM, Radom L (2006)
In search of radical intermediates in the reactions catalyzed by lysine 2,3-aminomutase and lysine 5,6-aminomutase.
Journal of the American Chemical Society 128, 16004-16005 [PubMed:17165731]
[show Abstract]
High-level ab initio calculations have been used to study radical intermediates in the reactions catalyzed by lysine 2,3-aminomutase (2,3-LAM) and lysine 5,6-aminomutase (5,6-LAM). The reactions of these enzymes with the substrate analogues 4-oxalysine (4-OL), 4-thialysine (4-TL), or trans-4,5-dehydrolysine (t-4,5-DL) are rationalized in terms of stabilization provided by the substituent to the adjacent radical center. Large changes in the exothermicity accompanying the initial H-abstraction are observed relative to the lysine reference values that follow the series 4-OL < 4-TL < t-4,5-DL. These changes have the primary effect of increasing the endothermicity for subsequent ring-closure to form the putative aziridinylcarbinyl radical intermediate. Such stabilization is consistent with experimental observations of the substrate-derived radical (S*) in the reaction of 2,3-LAM with 4-TL as well as the ability of t-4,5-DL to act as an irreversible inhibitor of 2,3-LAM. Our calculations suggest that 4-TL and trans-3,4-dehydrolysine may also permit experimental characterization of S* radicals in the reactions catalyzed by 5,6-LAM. Strategies for modifying PLP are presented that might lead to the first observation of the aziridinylcarbinyl radical intermediate (I*) in the aminomutase-catalyzed reactions. | Miller J, Bandarian V, Reed GH, Frey PA (2001)
Inhibition of lysine 2,3-aminomutase by the alternative substrate 4-thialysine and characterization of the 4-thialysyl radical intermediate.
Archives of biochemistry and biophysics 387, 281-288 [PubMed:11370852]
[show Abstract]
Lysine 2,3-aminomutase catalyzes the interconversion of L-lysine and L-beta-lysine. 4-Thia-L-lysine (4-thialysine) is an alternative substrate for Lysine 2,3-aminomutase. The organic free radical that appears in the steady state of the reaction of 4-thialysine is structurally analogous to the first lysine-based radical in the chemical mechanism (Wu, W., Lieder, K. W., Reed, G. H., and Frey, P. A. (1995) Biochemistry 34, 10532-10537). 4-Thialysine is a much more potent inhibitor of the reaction of lysine than would be anticipated on the basis of the value of Km for its reaction as a substrate. 4-Thialysine is here shown to be a competitive reversible inhibitor with respect to L-lysine, displaying an inhibition constant of 0.12 +/- 0.01 mM. The value of Km for 4-thialysine is 1.4 +/- 0.1 mM, and the maximum velocity Vm = 0.19 +/-0.02 micromol min(-1) mg-1 at 37 degrees C and pH 8.0. The kinetic parameters for the reaction of lysine under the same conditions are: Km = 4.2 +/- 0.5 mM and Vm = 43 +/- 1 micromol min(-1) mg(-1). The discrepancy between Km and the apparent Ki for 4-thialysine arises from the fact that the maximal velocity for 4-thialysine is only 0.44% that for L-lysine. The electron paramagnetic resonance spectra of the organic radical generated at the active site from 4-thialysine and those generated from deuterium and 3-13C-labeled forms of 4-thialysine were analyzed by simulation. Based on the resulting hyperfine splitting constants, the conformation and distribution of the unpaired spin of the radical at the active site were evaluated. | Wu W, Lieder KW, Reed GH, Frey PA (1995)
Observation of a second substrate radical intermediate in the reaction of lysine 2,3-aminomutase: a radical centered on the beta-carbon of the alternative substrate, 4-thia-L-lysine.
Biochemistry 34, 10532-10537 [PubMed:7654708]
[show Abstract]
Lysine 2,3-aminomutase from Clostridia catalyzes the interconversion of lysine and beta-lysine by a mechanism in which four organic radicals are postulated as intermediates. One of the intermediates has been identified as the alpha-radical of beta-lysine in imine linkage to pyridoxal phosphate (PLP) [Ballinger, M. D., Frey, P. A., & Reed, G. H. (1992) Biochemistry 31, 10782-10788]. We report here the observation of another of the four putative radical intermediates in the reaction of the alternative substrate, 4-thia-L-lysine (S-2-aminoethyl-L-cysteine). 4-Thialysine is a substrate for lysine 2,3-aminomutase. The Km of 4-thialysine is similar to that for lysine, and the Vm is approximately 3% of that for lysine. Upon mixing 4-thialysine with the activated enzyme in the presence of the required cofactor S-adenosylmethionine, followed by freeze-quenching with liquid N2 in the steady state, a strong EPR signal centered at g = 2.003 is observed. This signal exhibits strong hyperfine splitting due to the presence of 13C at carbon-3 of 4-thialysine, and the EPR pattern is narrowed upon the substitution of deuterium at carbon-3. The hyperfine interactions show that the unpaired electron is centered on carbon-3 of 4-thialysine. The hyperfine pattern in the EPR spectrum is also simplified by the use of 4-thia[5,6-2H4]lysine as the substrate, showing either that the spin is partially delocalized through the sulfur intervening between carbons-3 and -5 or that the conformation is such that protons at carbon-6 are close to carbon-3.(ABSTRACT TRUNCATED AT 250 WORDS) |
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