Synonyms: Duodopa® | Lodosyn® | MK 486 [4]
carbidopa is an approved drug (FDA (1977))
Compound class:
Synthetic organic
Comment: Carbidopa was originally approved by the FDA in combination with levodopa in 1975. It is an inhibitor of L-Aromatic amino-acid decarboxylase (a.k.a. L-Dopa decarboxylase) [1,4] that decreases the peripheral decarboxylation of levodopa to dopamine. The competitive or noncompetitive nature of carbidopa's interaction with L-Dopa decarboxylase is complex. Two published papers that discuss the kinetics of the inhibitor/enzyme interaction are [4] and [1], and from analysis of these it would appear that due to the slow dissociation of carbidopa from L-Dopa decarboxylase, once the enzyme/inhibitor complex has formed substrate is unable to displace the inhibitor. Carbidopa is described as a competitive inhibitor in these articles [2-3].
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References |
1. Borri-Voltattorni C, Minelli A, Borri P. (1977)
Interaction of L-alpha-methyl-alpha-hydrazino-3,4 dihydroxyphenylpropionic acid with dopa-decarboxylase from pig kidney. FEBS Lett, 75 (1): 277-80. [PMID:852589] |
2. Durso R, Evans JE, Josephs E, Szabo G, Evans B, Fernandez HH, Browne TR. (2000)
Variable absorption of carbidopa affects both peripheral and central levodopa metabolism. J Clin Pharmacol, 40 (8): 854-60. [PMID:10934669] |
3. Ho CS, Butt A, Semra YK, Swaminathan R. (1997)
Effect of carbidopa on the excretion of sodium, dopamine, and ouabain-like substance in the rat. Hypertension, 30 (6): 1544-8. [PMID:9403580] |
4. Waterhouse MJ, Chia YC, Lees GJ. (1979)
Inhibition of human and rat hepatic aminotransferase activity with L-3,4-dihydroxyphenylalanine by inhibitors of peripheral aromatic amino acid decarboxylase. Mol Pharmacol, 15 (1): 108-14. [PMID:423884] |