An undergraduate biochemistry student was working on glutathione peroxidase enzy

Question

An undergraduate biochemistry student was working on glutathione peroxidase enzyme from rat liver after exposing the experimental animals to toxic levels of cadmium for use in assessing the effect of cadmium toxicity on antioxidant status in the rat. She obtained the following results during extraction and characterization of the enzyme. Calculate the total activity, total protein concentration, specific activity, percent yield and purification fold. Indicate their units of measurements. Fill all the black spaces.

Explanation / Answer

Total protein concentration (mg) – Protein concentration multiplied by the total volume gives the total protein (i.e. mg/ml x ml = mg).
Total activity (units) – Activity multiplied by the total volume gives the total activity.
Specific-activity –The total activity divided by the total protein.
Purification (fold) – The purification is obtained by dividing the specific activity at any stage by the specific activity of the original homogenate.
Here since the values for original homogenate are not mentioned, we are assuming the salt precipitated sample to be the original and taking it as 1.
Yield (%) – The activity of the original homogenate is arbitrarily considered to be 100%. The yield (%) is calculated from the total activity at each step divided by the total activity in the homogenate, multiplied by 100.

Volume (ml) activity per ml protein concentration Total activity (units) Total protein concentration (mg) Specific activity (units/mg) Yield Fold 30-65% salt precipitation of the liver extract 710 1985.06 13.68 1409392.6 9712.8 145.10 100 1 Gel filtration 346 3024.90 6.70 1046615.4 2318.2 451.47 74.26 3.11 Ion exchange chromatography 48 6882.56 0.54 330362.88 25.92 12745.48 23.44 87.83 Affinity chromatography 20.4 9126.54 0.64 186181.416 13.05 14260.22 13.21 98.27

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