3-dimethylcysteine

https://www.ebi.ac.uk/chebi/searchId.do?chebiId=CHEBI:7959
http://www.genome.jp/dbget-bin/www_bget?drug:D00496
http://www.genome.jp/dbget-bin/www_bget?cpd:C07418
https://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=5852
https://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?sid=46508305
https://www.chemspider.com/Chemical-Structure.5643.html
http://www.bindingdb.org/bind/chemsearch/marvin/MolStructure.jsp?monomerid=39346
https://mor.nlm.nih.gov/RxNav/search?searchBy=RXCUI&searchTerm=7975
https://www.ebi.ac.uk/chebi/searchId.do?chebiId=7959
https://www.ebi.ac.uk/chembldb/index.php/compound/inspect/CHEMBL1430
https://zinc.docking.org/substances/ZINC000000114127
http://bidd.nus.edu.sg/group/cjttd/ZFTTDDRUG.asp?ID=DNC000575
http://www.pharmgkb.org/drug/PA450840
https://www.ebi.ac.uk/pdbe-srv/pdbechem/chemicalCompound/show/LEI
http://www.rxlist.com/cgi/generic3/penicillamine.htm
https://www.drugs.com/cdi/penicillamine.html
https://en.wikipedia.org/wiki/Penicillamine