What should be the positive result in polypeptide test? Pls help me..?
1. dissolve 1 pc chicken buoillon in 50ml of hot water.
2. pour 25ml of the dissolved chicken buoillon inside a 10 cm longganisa membrane.
3. make sure to tie both ends with string and check if there are leaks.
4. wash it with distilled water.
5. place it in a beaker with distilled water. 3/4 of the longganisa membrane should be dipped in the water.
6. leave it that way for an hour.
7. get 1ml of the dialysate (water in the beaker where the longganisa is sunk). add 2ml 10% NaOH then 5 drops of copper sulfate(aqueous).
8. observe the reaction.
Answer:
The reaction observed should be a change from a milky white to a sharp violet colour.
The NaOH hydrolyses the proteins, and the Cu2+ ions in copper sulphate form purple complexes with the proteins.
It usually works with high concentrations of proteins, the protein content in the chicken may have been too low.
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