Two students were assigned the task of purifying the enzyme alpha-galactosidase from a yeast extract.
After an initial centrifugation and dialysis of the crude extract, they employed batch (large-scale) and then column DEAE (diethyl-aminoethyl)-ion exchange chromatography. Following dialysis, the students then employed affinity chromatography.
After each step, the samples/fractions were assayed for enzyme activity and protein concentration. Active fractions were pooled and further processed.
A chart showing the results of the purification process is shown below. Note that the percent yield of enzyme activity (Units) and fold purification of the enzyme specific activity are only given for the starting material.
You should calculate these values for the remainder of the table and then choose the one statement below which correctly interprets the results of the purification scheme.
Purification Table of Alpha-Galactosidase from Yeast
|Step||Vol. (mL)||Total Activity (Units)||Total Protein (mg)||Specific Activity (U/mg protein)||Yield (%)||Purification Factor|
|Batch-DEAE Ion Exchange||42||22.8||1011||0.023||-||-|
|Column-DEAE Ion Exchange||15||12.2||480||0.025||-||-|