Carbonic anhydrase inhibitors: the very weak inhibitors dithiothreitol, beta-mercaptoethanol, tris(carboxyethyl)phosphine and threitol interfere with the binding of sulfonamides to isozymes II and IX.

Article Details

Citation

Innocenti A, Hilvo M, Scozzafava A, Lindfors M, Nordlund HR, Kulomaa MS, Parkkila S, Supuran CT

Carbonic anhydrase inhibitors: the very weak inhibitors dithiothreitol, beta-mercaptoethanol, tris(carboxyethyl)phosphine and threitol interfere with the binding of sulfonamides to isozymes II and IX.

Bioorg Med Chem Lett. 2008 Mar 15;18(6):1898-903. doi: 10.1016/j.bmcl.2008.02.008. Epub 2008 Feb 9.

PubMed ID
18295485 [ View in PubMed
]
Abstract

The inhibition of the metalloenzyme carbonic anhydrase (CA, EC 4.2.1.1) with dithiothreitol, 2-mercaptoethanol, tris(carboxyethyl)phosphine (reducing agent frequently added to enzyme assay buffers) and threitol has been investigated. The agents were very weak inhibitors of isozymes CA II and CA IX, but unexpectedly, strongly influenced the binding of the low nanomolar sulfonamide inhibitor acetazolamide (5-acetamido-1,3,4-thiadiazole-2-sulfonamide). Acetazolamide affinity for all investigated CAs diminished orders of magnitude with increasing concentrations of these agents in the assay system. DTT and similar derivatives should not be added to the assay buffers used in monitoring CA activity/inhibition, as they lead to under-estimation of the binding constants, by a mechanism probably involving the formation of ternary complexes.

DrugBank Data that Cites this Article

Binding Properties
DrugTargetPropertyMeasurementpHTemperature (°C)
AcetazolamideCarbonic anhydrase 2IC 50 (nM)53.1N/AN/ADetails
AcetazolamideCarbonic anhydrase 2IC 50 (nM)18.5N/AN/ADetails
AcetazolamideCarbonic anhydrase 2IC 50 (nM)34.3N/AN/ADetails
AcetazolamideCarbonic anhydrase 2IC 50 (nM)283N/AN/ADetails
AcetazolamideCarbonic anhydrase 2IC 50 (nM)68.6N/AN/ADetails
AcetazolamideCarbonic anhydrase 2IC 50 (nM)362N/AN/ADetails
AcetazolamideCarbonic anhydrase 2IC 50 (nM)89.9N/AN/ADetails
AcetazolamideCarbonic anhydrase 2IC 50 (nM)8.9N/AN/ADetails
AcetazolamideCarbonic anhydrase 2IC 50 (nM)16.2N/AN/ADetails
AcetazolamideCarbonic anhydrase 2IC 50 (nM)68N/AN/ADetails
AcetazolamideCarbonic anhydrase 2IC 50 (nM)47.6N/AN/ADetails
AcetazolamideCarbonic anhydrase 2IC 50 (nM)48.1N/AN/ADetails
AcetazolamideCarbonic anhydrase 2IC 50 (nM)77.8N/AN/ADetails
AcetazolamideCarbonic anhydrase 2IC 50 (nM)48.9N/AN/ADetails
AcetazolamideCarbonic anhydrase 2IC 50 (nM)48.3N/AN/ADetails
AcetazolamideCarbonic anhydrase 2IC 50 (nM)56.5N/AN/ADetails
AcetazolamideCarbonic anhydrase 2IC 50 (nM)60.4N/AN/ADetails
AcetazolamideCarbonic anhydrase 2IC 50 (nM)36N/AN/ADetails
AcetazolamideCarbonic anhydrase 2IC 50 (nM)441N/AN/ADetails
AcetazolamideCarbonic anhydrase 2IC 50 (nM)285N/AN/ADetails
AcetazolamideCarbonic anhydrase 2IC 50 (nM)69.7N/AN/ADetails
AcetazolamideCarbonic anhydrase 2IC 50 (nM)92.5N/AN/ADetails
AcetazolamideCarbonic anhydrase 2IC 50 (nM)98.3N/AN/ADetails
AcetazolamideCarbonic anhydrase 2IC 50 (nM)351N/AN/ADetails