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]

S-Methylcysteine
Names
IUPAC name
S-Methyl-L-cysteine
Systematic IUPAC name
2-amino-3-(methylthio)propanoic acid
Other names
3-methylthioalanine
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard 100.013.365 Edit this at Wikidata
EC Number
  • L-enantiomer: 214-701-6
KEGG
UNII
  • 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
  • L-enantiomer: CSC[C@@H](C(=O)O)N
Properties
C4H9NO2S
Molar mass 135.18 g·mol−1
Appearance white solid
Melting point 248 °C (478 °F; 521 K)
Hazards
GHS labelling:
GHS07: Exclamation mark
Warning
H302, H315, H319, H335
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).

Natural occurrence

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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 onions.[4]

Other chemical properties

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

References

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  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.