Biochemistry question Tm 315K Delta Hunfolding Tm 551 kJmo

Biochemistry question:

Tm= 315K ;

Delta H(unfolding) (@Tm) = +551 kJ/mol;

Delta Cp = +6.3 kJ/mol*K

a. Calculate delta S unfolding.

b. Estimate how many Angstroms^2 of non-polar surface area are buried upon folding of lysozyme.

c. By rough calculation,k is burial of non-polar surface area sufficient to overcome the entropic barrier to lysozyme folding at 298K?

Solution

The equation between enthalpy and specific heat is H = CpT; to calculate entropy of unfolding we use that formula because the state is not changed yet.

S = Cp x lnTm where ln is natural log

= 6.3 x ln 315 = 6.3 x 2.3 log315

S = 6.3 x 2.3 x 2.5 = 36.225 Kj ⁰C/mol

The non-polar surface is 1.5 times to polar surface of lysozyme. For 2 angstrom lysozyme surface=

(1.5/2.5) x 2 = 1.2 angstrom