[rfaraday]

I calculated that the denaturation enthalpy and entropy changes for chymotrypsin are:
H = 418 kj/mol
S= 1.32 kj/mol(K)

Assume that, in the denatuartd state, each amino acid had three possible orientations. estimate number of amino acid in chymotrypsin using the value of the denaturation change given above. How would it change if you assume each a.a. has 4 possible orientations.

I am not really sure how to begin. I think I may have to use

S = k_b ln w or perhaps boltzmann equation but I am not give a temperature.

[Yggdrasil]

I think S = k_b ln w is the best equation to use in this case.  You can assume that for a folded protein, each amino acid will have only one possible orientation.

[rfaraday]

I use that and I get an answer that is unreasonable on the order of 1e25. i think the protein has around 250ish. Any chance I should use R ln w. I have seen that equation used in the literature.

[Yggdrasil]

Of course.  Since ?S is given in units of kJ/mol K, you should use R = k_b/N_A since R has units of J/mol K.  If ?S were given in units of kJ/K, then you would want to use k_b.  Moral of the story: always make sure your units match.