A purified oligomeric protein was analysed by SDS - Page under reducing and non reducing conditions. A 1 litre solution of 1mg/ml concentration has 4.01*10^18 molecules of the oligomeric protein. Based on the figure deduce the total no. of polypeptide chains that constitute this protein.
Hi there,
The native protein contains 50kDa and 25kDa polypeptides interacting covalently through at least one disulfide bridge. If the native protein is a 1mg/mL solution then concentration in the 75kDa unit is 1/75000= 13, 3µM which represents 13.3*10-6*6.02*1023 molecules which is 8.03*1018 molecules . Then it is twice the number indicated then native protein is an assembly of 2 75kDa subunit .
It is just impossible to guess the oligomerization of a protein using this technique. The only technique that is accurate is analytical centrifugation. You can also have an approximation using gel filtration with good standards.
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