S-Methylcysteine

S-Methylcysteine
Names
	IUPAC name 2-amino-3-(methylthio)propanoic acid
	Other names 3-methylthioalanine
Identifiers
CAS Number	L-enantiomer: 1187-84-4;
3D model (JSmol)	L-enantiomer: Interactive image;
ChEBI	L-enantiomer: CHEBI:45658;
ChEMBL	L-enantiomer: ChEMBL394875;
ChemSpider	L-enantiomer: 22826;
DrugBank	L-enantiomer: 02216;
ECHA InfoCard	100.013.365
EC Number	L-enantiomer: 214-701-6;
KEGG	L-enantiomer: C22040;
PubChem CID	L-enantiomer: 24417;
UNII	L-enantiomer: A34I1H07YM;
CompTox Dashboard (EPA)	L-enantiomer: DTXSID50862579 ;
	InChI InChI=1S/C4H9NO2S/c1-8-2-3(5)4(6)7/h3H,2,5H2,1H3,(H,6,7)/t3-/m0/s1 Key: IDIDJDIHTAOVLG-VKHMYHEASA-N;
	SMILES L-enantiomer: CSC[C@@H](C(=O)O)N;
Properties
Chemical formula	C4H9NO2S
Molar mass	135.18 g·mol−1
Appearance	white solid
Melting point	248 °C (478 °F; 521 K)
Hazards
	GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H302, H315, H319, H335
Precautionary statements	P261, P264, P270, P271, P280, P301+P312, P302+P352, P304+P340, P305+P351+P338, P312, P321, P330, P332+P313, P337+P313, P362, P403+P233, P405, P501
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

S-Methylcysteine is the amino acid with the nominal formula CH₃SCH₂CH(NH₂)CO₂H. It is the S-methylated derivative of cysteine. This amino acid occurs widely in plants, including many edible vegetables.^[1]

Biosynthesis

The amino acid is not genetically coded, but it arises by post-translational methylation of cysteine. One pathway involves methyl transfer from alkylated DNA by zinc-cysteinate-containing repair enzymes.^[2]^[3]

Beyond its biological context, it has been examined as a chelating agent.^[4]

References

^ Maw, George A. (1982). "Biochemistry of S-Methyl-L-Cysteine and its Principal Derivatives". Sulfur Reports. 2: 1–26. doi:10.1080/01961778208082422.
^ Sors, Thomas G.; Ellis, Danielle R.; Na, Gun Nam; Lahner, Brett; Lee, Sangman; Leustek, Thomas; Pickering, Ingrid J.; Salt, David E. (2005). "Analysis of Sulfur and Selenium Assimilation in Astragalus plants with Varying Capacities to Accumulate Selenium". The Plant Journal. 42 (6): 785–797. doi:10.1111/j.1365-313X.2005.02413.x. PMID 15941393.
^ Clarke, Steven G. (2018). "The ribosome: A Hot Spot for the Identification of New Types of Protein Methyltransferases". Journal of Biological Chemistry. 293 (27): 10438–10446. doi:10.1074/jbc.AW118.003235. PMC 6036201. PMID 29743234.
^ He, Haiyang; Lipowska, Malgorzata; Xu, Xiaolong; Taylor, Andrew T.; Carlone, Maria; Marzilli, Luigi G. (2005). "Re(CO)₃ Complexes Synthesized via an Improved Preparation of Aqueousfac-[Re(CO)₃(H2O)₃]+as an Aid in Assessing ^99m Tc Imaging Agents. Structural Characterization and Solution Behavior of Complexes with Thioether-Bearing Amino Acids as Tridentate Ligands". Inorganic Chemistry. 44 (15): 5437–5446. doi:10.1021/ic0501869. PMID 16022542.

[1] Maw, George A. (1982). "Biochemistry of S-Methyl-L-Cysteine and its Principal Derivatives". Sulfur Reports. 2: 1–26. doi:10.1080/01961778208082422.

[2] Sors, Thomas G.; Ellis, Danielle R.; Na, Gun Nam; Lahner, Brett; Lee, Sangman; Leustek, Thomas; Pickering, Ingrid J.; Salt, David E. (2005). "Analysis of Sulfur and Selenium Assimilation in Astragalus plants with Varying Capacities to Accumulate Selenium". The Plant Journal. 42 (6): 785–797. doi:10.1111/j.1365-313X.2005.02413.x. PMID 15941393.

[3] Clarke, Steven G. (2018). "The ribosome: A Hot Spot for the Identification of New Types of Protein Methyltransferases". Journal of Biological Chemistry. 293 (27): 10438–10446. doi:10.1074/jbc.AW118.003235. PMC 6036201. PMID 29743234.

[4] He, Haiyang; Lipowska, Malgorzata; Xu, Xiaolong; Taylor, Andrew T.; Carlone, Maria; Marzilli, Luigi G. (2005). "Re(CO)₃ Complexes Synthesized via an Improved Preparation of Aqueousfac-[Re(CO)₃(H2O)₃]+as an Aid in Assessing ^99m Tc Imaging Agents. Structural Characterization and Solution Behavior of Complexes with Thioether-Bearing Amino Acids as Tridentate Ligands". Inorganic Chemistry. 44 (15): 5437–5446. doi:10.1021/ic0501869. PMID 16022542.

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