In Wilson's disease, a rare genetic disorder of copper metabolism, penicillamine treatment relies on its binding to accumulated copper and elimination through urine.[4]Succimer (dimercaptosuccinic acid) is increasingly used in place of penicillamine.[5]
In cystinuria, a hereditary disorder in which high urine cystine levels lead to the formation of cystine stones, penicillamine binds with cysteine to yield a mixed disulfide which is more soluble than cystine.[8]
Penicillamine can be used as a disease-modifying antirheumatic drug (DMARD) to treat severe active rheumatoid arthritis in patients who have failed to respond to an adequate trial of conventional therapy,[10] although it is rarely used today due to availability of TNF inhibitors and other agents, such as tocilizumab and tofacitinib. Penicillamine works by reducing numbers of T-lymphocytes, inhibiting macrophage function, decreasing IL-1, decreasing rheumatoid factor, and preventing collagen from cross-linking.
Penicillamine is a trifunctional organic compound, consisting of a thiol, an amine, and a carboxylic acid. It is an amino acid structurally similar to cysteine, but with geminal dimethyl substituents α to the thiol. Like most amino acids, it is a colorless solid that exists in the zwitterionic form at physiological pH. The acid-base properties of penicillamine and cysteine are very similar. The pKa for the carboxylic acid is 1.8 for both, and the pKa for the thiol and ammonium groups are 10.8 (cys) and 10.5 and 8.3 (cys) and 7.9.[19]
Penicillamine is chiral molecule. The natural form has the opposite configuration from the one seen for natural cysteine.[19] The two enantiomers have distinct physiological effects. (S)-penicillamine (D-penicillamine, having (–) optical rotation) is used as aa drug (a chiral drug).[20](R)-penicillamine (L-penicillamine, having (+) optical rotation) is toxic because it inhibits the action of pyridoxine (also known as vitamin B6).[21]D-penicillamine is a metabolite of penicillin but has no antibiotic properties itself. A variety of metal complexes derived from penicillamine are known.[22] For example, copper form large clusters.[23]
History
John Walshe first described the use of penicillamine in Wilson's disease in 1956.[24] He had discovered the compound in the urine of patients (including himself) who had taken penicillin, and experimentally confirmed that it increased urinary copper excretion by chelation. He had initial difficulty convincing several world experts of the time (Denny-Brown and Cumings) of its efficacy, as they held that Wilson's disease was not primarily a problem of copper homeostasis but of amino acid metabolism, and that dimercaprol should be used as a chelator. Later studies confirmed both the copper-centered theory and the efficacy of D-penicillamine. Walshe also pioneered other chelators in Wilson's such as triethylene tetramine and tetrathiomolybdate.[25]
↑World Health Organization model list of essential medicines: 21st list 2019. Geneva: World Health Organization. 2019. hdl:10665/325771. WHO/MVP/EMP/IAU/2019.06. License: CC BY-NC-SA 3.0 IGO.
↑Peisach J, Blumberg WE (March 1969). "A mechanism for the action of penicillamine in the treatment of Wilson's disease". Molecular Pharmacology. 5 (2): 200–209. doi:10.1016/S0026-895X(25)14659-2. PMID4306792.
↑Grasedyck K (1988). "D-penicillamine--side effects, pathogenesis and decreasing the risks". Zeitschrift für Rheumatologie. 47 (Suppl 1): 17–19. PMID3063003.
12Yoshinari N, Konno T (2018). "Chiral Phenomena in Multinuclear and Metallosupramolecular Coordination Systems Derived from Metalloligands with Thiol-Containing Amino Acids". Bulletin of the Chemical Society of Japan. 91 (5): 790–812. doi:10.1246/bcsj.20180032.
↑Ariens EJ (1989). Chiral Separations by HPLC. Chichester: Ellis Horwwod, Chichester. pp.31–68.
↑Yoshinari N, Konno T (2018). "Chiral Phenomena in Multinuclear and Metallosupramolecular Coordination Systems Derived from Metalloligands with Thiol-Containing Amino Acids". Bulletin of the Chemical Society of Japan. 91 (5): 790–812. doi:10.1246/bcsj.20180032.
↑Birker PJ, Freeman HC (October 1977). "Structure, properties, and function of a copper(I)-copper(II) complex of D-penicillamine: pentathallium(I) μ8-chloro-dodeca(D-penicillaminato)-octacuprate(I)hexacuprate(II) n-hydrate". Journal of the American Chemical Society. 99 (21): 6890–6899. doi:10.1021/ja00463a019. PMID903530.
↑Jaffe IA (September 1964). "Rheumatoid Arthritis with Arteritis; Report of a Case Treated with Penicillamine". Annals of Internal Medicine. 61: 556–563. doi:10.7326/0003-4819-61-3-556. PMID14218939.
External links
"Penicillamine". Drug Information Portal. U.S. National Library of Medicine. Archived from the original on 28 June 2019.
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