Calculation of volume excluded by lysozyme

On the basis of a 25 mg/mL solution, assuming a density of the protein of 1.3, we get an excluded volume of 19uL per mL or 1.9% of the volume.

The molecular formula for lysozyme (calculated at ExPASy with ProtParam program) is C705H1116N214O204S12 (2251 atoms total, MW is 16238.6)

So as to use the same numbers as have been calculated for the buffers we will just assume 2% as our densities and concentrations are not accurate enough to justify higher precision.

So for each atom I need 2% of the molar atomic composition of the protein as follows:

Atom	mols in 1 mol lys	molar proportion	2% amount(25 mg/mL)	10mg/mL	5 mg/mL	2 mg/mL
C	705	0.313	0.00626	0.00250	0.00125	5E-4
H	1116	0.496	0.00992	0.003968	0.00199	7.9E-4
N	214	0.0951	0.00190	0.00076	3.8E-4	1.52E-4
O	204	0.0906	0.00181	0.000724	3.62E-4	1.5E-4
S	12	0.00533	0.000107	0.0000428	2.14E-5	8.6E-6