S-Methylcysteine

S-Methylcysteine
Names
	IUPAC name S-Methyl-L-cysteine
	Systematic 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]

Natural occurrence

S-Methylcysteine 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]

S-Methylcysteine sulfoxide is an oxidized derivative of S-methylcysteine that is found in [onion]]s.^[4]

Other chemical properties

Beyond its biological context, S-methylcysteine has been examined as a chelating agent.^[5]

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.
^ Bernaert, N.; Goetghebeur, L.; De Clercq, H.; De Loose, M.; Daeseleire, E.; Van Pamel, E.; Van Bockstaele, E.; Van Droogenbroeck, B. (2012). "Influence of Cultivar and Harvest Time on the Amounts of Isoalliin and Methiin in Leek (Allium ampeloprasum var. porrum)". Journal of Agricultural and Food Chemistry. 60 (44): 10910–10919. doi:10.1021/jf302132a. PMID 23020262.
^ 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] Bernaert, N.; Goetghebeur, L.; De Clercq, H.; De Loose, M.; Daeseleire, E.; Van Pamel, E.; Van Bockstaele, E.; Van Droogenbroeck, B. (2012). "Influence of Cultivar and Harvest Time on the Amounts of Isoalliin and Methiin in Leek (Allium ampeloprasum var. porrum)". Journal of Agricultural and Food Chemistry. 60 (44): 10910–10919. doi:10.1021/jf302132a. PMID 23020262.

[5] 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]

[2]

[3]

[4]

[5]

Names

IUPAC name S-Methyl-L-cysteine
Systematic 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