(a) A student from BCHM 2114 analyses bovine serum albumin (BSA)
with a polyacrylamide gel electrophoresis (PAGE-SDS). During the
experiment, the student forgets to add β- mercaptoethanol to the
sample. When comparing his sample to those of his classmates he
realizes that the molecular mass of his BSA sample determined by
PAGE-SDS is 57 kDa, while all the other students (those that added
β-mercaptoethanol) found a molecular mass of 68 kDa. Explain this
difference.

(b) A sample of the glycolytic enzyme enolase (molecular weight,
63,000) was contaminated by lactate dehydrogenase (molecular
weight, 152,000). Suggest a chromatographic method whereby the two
enzymes can be separated and explain the basis of the
separation.