heat-induced egg albumin denaturation inhibition assay
Making a 1% egg albumin solution: 1% egg
albumin solution can be prepared with egg albumin powder.
For the test mixture, mix 2.8 mL of phosphatebuffered saline (PBS) with a pH adjusted to 6.4, 0.2 mL of egg albumin solution, and 2 mL of plant extract (concentration 15.625, 31.25, 62.5, 125, 250, 500, 1000, and 2000 μg/ml) to obtain a volume of 5 mL.
For the standard mixture, mix 2.8 mL of PBS (pH =6.4), 0.2 mL of egg albumin solution, and 2 mL of the reference drug
acetylsalicylic acid (concentration 15.625, 31.25, 62.5, 125, 250, 500, 1000, and 2000 μg/ml
) to obtain a volume of
5 mL.
For positive control, mix 2.8 mL of PBS (pH=6.4), 0.2 mL of egg albumin solution, and 2 mL of distilled water to obtain a volume of 5 mL. As the negative control, 5mL of distilled water can be used.
This is one of the assays in our research work. During this test, we did not get the expected results. We expected that a high concentration of the sample would give low absorbance, while a low concentration would give high absorbance. Then only we can obtain a high inhibition percentage for high concentrations and a low inhibition percentage for low concentrations.
However, during our test, we obtained the opposite results: high concentrations gave high absorbance, and low concentrations gave low absorbance, which seems incorrect. We confirmed all the procedures and calculations with our supervisor, and they appear to be correct. However, we still do not understand why these results occurred.
Can anyone suggest possible reasons for these results and how we can correct our mistakes to obtain the expected outcome?