1. Protein A folds in water @ 37 oCto form 2 hydrogen bonds (-1.1 kcal/mol) and

Question

1. Protein A folds in water @ 37 oCto form 2 hydrogen bonds (-1.1 kcal/mol) and a hydrophobic interaction (-3 kcal/mol). –Draw reaction –Write total delta G for folding – what is the ratio of folded to unfolded protein? –Whatsthe difference without the hydrophobic interaction?

2. The reaction of a substance with an enzyme has a delta G of 2kJ/mol. The product enzyme is no longer functional –Write the reaction –If you eat the substance how much modified protein do you have?

3. I went into lab and measured the folding of protein A since the folded form has a different color. The temp was 37 degrees Celsius. I found the ratio of folded to unfolded to be 25 (folded) to 1(unfolded). What is delta G in cals?

Explanation / Answer

Answer-

1) Different states of protein are native state, intermediate and unfolded state.

Delta is the Gibbs free energy change..

For protein moving from folded to unfloded state energy is releasing.

Gibbs free energy equation is Keq"="e^((G/kT)

The non-polar or hydrophobic groups altogether away from the interaction.

2) If the delta G of 2kJ/mol.The product of enzymen is no longer functional. The reaction would be as follows

Keq"="e^(((G/kT)

hence

Keq"="e^(((((H(TS))/kt)=e^(((TS(H))/kt)

3) As the temperature is at 37 degree i.e room temperature = 300K

The folded to unfolded 25 to 1.

The delta G in cal will be

S = k ln(2) – k ln(1)

Here refers to the number of possible conformations

Since this is a negative number, the entropy decreased (i.e. the disorder decreased).

When we apply the free energy equation, we see that the free energy change is positive, as it should be for a decrease in disorder. G=-Ts

=+ 2.61 K cal

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