Description
Indole Assay Kit (Colorimetric) (BA0046) (BA0046)
The Indole Assay Kit (Colorimetric) (SKU: BA0046) provides a fast and sensitive method for the quantitative colorimetric determination of indole in biological samples. Indole is the primary product of tryptophan breakdown by tryptophanase, and the indole test is commonly performed on bacteria to classify them by their ability to break down tryptophan to indole. The kit is based on a modified version of Ehrlich's and Kovac's reagents, which react with indole to produce a coloured compound at 565nm. The intensity of this coloured compound is directly proportional to the indole in the sample. The convenient procedure involves adding a single working reagent and reading the absorbance immediately, using 100 µL of sample. This makes the kit well suited to microbiological research applications.
| Product Name: | Indole Assay Kit (Colorimetric) (BA0046) |
| SKU: | BA0046 |
| Detection Method: | Colorimetric |
| Detection Range: | 3 to 100 µM indole in 96-well plate assay |
| Sample Type: | Biological samples (e.g. indole produced by indole-positive bacteria) |
| Species Reactivity: | All |
| Assay Time: | Immediate read after reagent addition |
| Kit Size: | 100 Assays |
| Equipment Required: | Microplate reader |
| Storage: | The kit is shipped at room temperature. Store all components at 4°C upon receipt. |
| Shelf Life: | 6 months after receipt |
| Shipping: | Room Temperature |
This kit is based on a modified version of Ehrlich's and Kovac's reagents, which react with indole to produce a coloured compound at 565nm. The intensity of the coloured compound is directly proportional to the indole in the sample.
- Fast and sensitive: use of 100 µL sample; linear detection range from 3 to 100 µM indole in 96-well plate assay
- Convenient: the procedure involves adding a single working reagent and reading the absorbance immediately
- Direct assays: indole in biological samples (e.g. indole produced by indole-positive bacteria)
Note: The below protocol is a sample protocol. Protocols are specific to each batch/lot. For the correct instructions please follow the protocol included in your kit.
| Step | Procedure |
| 1 | Standards: prepare 1 mL of 100 µM Premix by mixing 10 µL of the 10 mM Standard and 990 µL of blank medium (e.g. bacterial growth medium), then dilute standards in 1.5-mL centrifuge tubes as shown in the table. |
| 2 | Transfer 100 µL standards into separate wells of a clear, flat-bottom 96-well plate and 100 µL of each sample into separate wells. |
| 3 | Add 100 µL Reagent to the four standards and the sample wells; tap plate to mix briefly and thoroughly. |
| 4 | Read optical density at 565nm (520-590nm). |
Subtract the blank value (#4) from the standard values and plot ∆OD against standard concentrations. Determine the slope and calculate indole concentration = (ODSAMPLE − ODBLANK) / Slope (µM), where ODSAMPLE and ODBLANK are OD readings of the sample and media blank (#4). Conversion: 1 µM indole equals 11.7 µg/dL or 117 ppm.
| Component | Quantity | Storage |
| Reagent | 12 mL | 4°C |
| Standard (10 mM Indole) | 100 µL | 4°C |
| Leonardi et al. | Characterisation of novel functionality within the Blastocystis tryptophanase gene | PLoS Neglected Tropical Diseases 2021 | PMID: 34492012 |
