Acid Yellow 36 (Metanil Yellow) is an azo dye and pH indicator, changing color from red at pH 1.2 to yellow at pH 2.3.

Instructions
I. Solution preparation
1. Stock solution: Dissolve Acid Yellow 36 in an appropriate solvent, usually water or alcohol solvent, to prepare a stock solution with a concentration of 1–10 mM.
2. Working solution: Depending on the experimental requirements, the stock solution can be diluted to an appropriate concentration, usually 10–100 µM. Buffer (such as PBS, pH 7.4) or other solutions required for the experiment can be used for dilution.
II. Operation steps
1. pH indicator use: Acid Yellow 36 can be used to determine changes in pH, especially in the acidic range (pH 1.2-2.3), where the color changes from red to yellow. Adding Acid Yellow 36 directly to the dye solution can be used to monitor pH changes.
2. P-450 enzyme and cytosolic enzyme induction experiment: Acid Yellow 36 is used as an inducer of P-450 specific isozymes and cytosolic enzymes. In cell culture, the addition of Acid Yellow 36 can stimulate the activity of the corresponding enzymes and is suitable for studying the functions of these enzymes.
3. Cell experiments: Acid Yellow 36 is added to the cell culture medium, and the concentration range is usually 10–50 µM.
4. Enzyme activity detection: Use enzymatic methods (such as enzyme-linked immunosorbent assay ELISA or chromatography) to detect the activity of P-450 enzymes or cytosolic enzymes.
5. Calibration and control
1) Control group: Set up an experimental group without the addition of Acid Yellow 36 to ensure the specificity of enzyme induction.
2) Standard curve: A standard curve between dye concentration and color change can be established by using Acid Yellow 36 solutions with known concentrations.
Notes
1) Photosensitivity: Like many azo dyes, Acid Yellow 36 is sensitive to light and should be avoided from prolonged exposure to strong light.
2) Storage conditions: Acid Yellow 36 should be stored in a dry, cool place, away from heat and light, usually stored at -20°C.
3) Solubility: Acid Yellow 36 has good solubility in water, but it should be ensured that there are no undissolved solid particles.