hi,
it would be nice to know at what different wavelength you have taken your absorbance. for proteins absorbance is usually measured at 280nm ( which is the absorbance maxima for the aromatic side chains ) so depending on the number of aromatic rings present in the protein you will get the absorbance values. OD 600 in when you measure the absorbance at 600nm wavelength, this is usually the absorbance maxima for nucleic acids and by checking the OD at 600nm you know how much nucleic acid contamination you have in your protein solution.
