Question

2. For the following molecules, which method would you use to separate them?

Gel filtration chromatography or Ion-exchange

chromatography?

A) Glucose oxidase (M.W. 160 kDa, pI 4.8) and lactate dehydrogeanse ( M.W. 140 kDa, pI 8.0) B) Glucose Oxidase ( M.W. 160 kDa, pI 4.8) and beta galactosidase (M.W. 500 kDa, pI 4.5)

Answer 1

2) Gel filtration chromatography separate the molecule on the basis of size and ion exchange chromatography separate molecules on the basis of charge.

A) Since both molecules have comparable molecular weight thus, their size are also comparable hence gel filtration chromatography can't be used. Thus, ion exchange chromatography is used.

B) Since both molecules have comparable pI hence comparable charge. Thus, ion exchange chromatography can't be used to separate them. Hence, gel filtration chromatography is used.

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