I've been tasked with using DTNB to find the number of thiol groups on a molecule of Bovine Serum albumin (BSA).
After measuring the absorbance, finding the concentration of TNB and calculating the concentration of the BSA, I've come out with a result of around 0.4 free thiol groups per molecule of BSA, which seems unlikely! There is either a free group or there isn't!
Yet, the implication from the demonstrator is that is is the correct result!
How can this be? Is it possible to get a value of less than one in an experiment like this?