Protein

Enzyme activity: practice problems

Work out the result for enzyme activity. Every answer here is computed by the same tested calculator the rest of the site uses, so a solution can never drift away from the maths.

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Problem 1 Enzyme activity

Work out the result for enzyme activity.

  • Activity (U/mL): 50
  • Volume (mL): 2
  • Protein (mg/mL): 5.5
Show the answer and the working

Specific activity is 9.091 U/mg.

  1. Total units: unitsPerMl · volumeMl = 50 U/mL · 2 mL = 100 U
  2. Total protein: proteinMgPerMl · volumeMl = 5.5 mg/mL · 2 mL = 11 mg
  3. Specific activity: totalUnits / totalProteinMg = 100 U / 11 mg = 9.091 U/mg

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Problem 2 Enzyme activity

Work out the result for enzyme activity.

  • Activity (U/mL): 15
  • Volume (mL): 2.5
  • Protein (mg/mL): 6
Show the answer and the working

Specific activity is 2.5 U/mg.

  1. Total units: unitsPerMl · volumeMl = 15 U/mL · 2.5 mL = 37.5 U
  2. Total protein: proteinMgPerMl · volumeMl = 6 mg/mL · 2.5 mL = 15 mg
  3. Specific activity: totalUnits / totalProteinMg = 37.5 U / 15 mg = 2.5 U/mg

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Problem 3 Enzyme activity

Work out the result for enzyme activity.

  • Activity (U/mL): 10
  • Volume (mL): 1.5
  • Protein (mg/mL): 3
Show the answer and the working

Specific activity is 3.333 U/mg.

  1. Total units: unitsPerMl · volumeMl = 10 U/mL · 1.5 mL = 15 U
  2. Total protein: proteinMgPerMl · volumeMl = 3 mg/mL · 1.5 mL = 4.5 mg
  3. Specific activity: totalUnits / totalProteinMg = 15 U / 4.5 mg = 3.333 U/mg

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Problem 4 Enzyme activity

Work out the result for enzyme activity.

  • Activity (U/mL): 50
  • Volume (mL): 2
  • Protein (mg/mL): 7
Show the answer and the working

Specific activity is 7.143 U/mg.

  1. Total units: unitsPerMl · volumeMl = 50 U/mL · 2 mL = 100 U
  2. Total protein: proteinMgPerMl · volumeMl = 7 mg/mL · 2 mL = 14 mg
  3. Specific activity: totalUnits / totalProteinMg = 100 U / 14 mg = 7.143 U/mg

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Problem 5 Enzyme activity

Work out the result for enzyme activity.

  • Activity (U/mL): 50
  • Volume (mL): 3
  • Protein (mg/mL): 4.5
Show the answer and the working

Specific activity is 11.11 U/mg.

  1. Total units: unitsPerMl · volumeMl = 50 U/mL · 3 mL = 150 U
  2. Total protein: proteinMgPerMl · volumeMl = 4.5 mg/mL · 3 mL = 13.5 mg
  3. Specific activity: totalUnits / totalProteinMg = 150 U / 13.5 mg = 11.11 U/mg

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Problem 6 Enzyme activity

Work out the result for enzyme activity.

  • Activity (U/mL): 25
  • Volume (mL): 1.5
  • Protein (mg/mL): 4.5
Show the answer and the working

Specific activity is 5.556 U/mg.

  1. Total units: unitsPerMl · volumeMl = 25 U/mL · 1.5 mL = 37.5 U
  2. Total protein: proteinMgPerMl · volumeMl = 4.5 mg/mL · 1.5 mL = 6.75 mg
  3. Specific activity: totalUnits / totalProteinMg = 37.5 U / 6.75 mg = 5.556 U/mg

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Problem 7 Enzyme activity

Work out the result for enzyme activity.

  • Activity (U/mL): 50
  • Volume (mL): 1.5
  • Protein (mg/mL): 5
Show the answer and the working

Specific activity is 10 U/mg.

  1. Total units: unitsPerMl · volumeMl = 50 U/mL · 1.5 mL = 75 U
  2. Total protein: proteinMgPerMl · volumeMl = 5 mg/mL · 1.5 mL = 7.5 mg
  3. Specific activity: totalUnits / totalProteinMg = 75 U / 7.5 mg = 10 U/mg

Open this in the calculator to change the numbers.

Problem 8 Enzyme activity

Work out the result for enzyme activity.

  • Activity (U/mL): 50
  • Volume (mL): 2
  • Protein (mg/mL): 5
Show the answer and the working

Specific activity is 10 U/mg.

  1. Total units: unitsPerMl · volumeMl = 50 U/mL · 2 mL = 100 U
  2. Total protein: proteinMgPerMl · volumeMl = 5 mg/mL · 2 mL = 10 mg
  3. Specific activity: totalUnits / totalProteinMg = 100 U / 10 mg = 10 U/mg

Open this in the calculator to change the numbers.

Problem 9 Enzyme activity

Work out the result for enzyme activity.

  • Activity (U/mL): 25
  • Volume (mL): 2
  • Protein (mg/mL): 5
Show the answer and the working

Specific activity is 5 U/mg.

  1. Total units: unitsPerMl · volumeMl = 25 U/mL · 2 mL = 50 U
  2. Total protein: proteinMgPerMl · volumeMl = 5 mg/mL · 2 mL = 10 mg
  3. Specific activity: totalUnits / totalProteinMg = 50 U / 10 mg = 5 U/mg

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Problem 10 Enzyme activity

Work out the result for enzyme activity.

  • Activity (U/mL): 30
  • Volume (mL): 5
  • Protein (mg/mL): 4.5
Show the answer and the working

Specific activity is 6.667 U/mg.

  1. Total units: unitsPerMl · volumeMl = 30 U/mL · 5 mL = 150 U
  2. Total protein: proteinMgPerMl · volumeMl = 4.5 mg/mL · 5 mL = 22.5 mg
  3. Specific activity: totalUnits / totalProteinMg = 150 U / 22.5 mg = 6.667 U/mg

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More protein practice

Same topic, different calculation

Protein by A280

Protein concentration from absorbance and extinction coefficient.

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Open the Enzyme activity calculator