Many enzymes are inhibited irreversibly by heavy metal ions such as Hg2+, Cu2+, or Ag+, which can react with essential sulfhydryl groups to form mercaptides. Enz-SH+Ag+⟶Enz-S-Ag+H + The affinity of Ag + for sulfhydryl groups is so great that Ag + can be used to titrate - SH groups quantitatively. To 10.0 mL of a solution containing 1.3 mg/mL of a pure enzyme, an investigator added just enough AgNO3 to completely inactivate the enzyme. A total of 0.436 μmol AgNO3 was required. Calculate the minimum molecular weight (? r) of the enzyme.

Question

Maribel Daugherty

Chemistry

8 June, 21:05

Many enzymes are inhibited irreversibly by heavy metal ions such as Hg2+, Cu2+, or Ag+, which can react with essential sulfhydryl groups to form mercaptides. Enz-SH+Ag+⟶Enz-S-Ag+H + The affinity of Ag + for sulfhydryl groups is so great that Ag + can be used to titrate - SH groups quantitatively. To 10.0 mL of a solution containing 1.3 mg/mL of a pure enzyme, an investigator added just enough AgNO3 to completely inactivate the enzyme. A total of 0.436 μmol AgNO3 was required. Calculate the minimum molecular weight (? r) of the enzyme.

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Answers (1)

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Lyric Knox · Answer 1

The minimum molecular weight of the enzyme is 29.82 g/mol

Explanation:

Step 1: Given data

The volume of the solution = 10 ml = 10*10^-3L

Molarity of the solution = 1.3 mg/ml

moles of AgNO3 added = 0.436 µmol = 0.436 * 10^-3 mmol

Step 2: Calculate the mass

Density = mass / volume

1.3mg/mL = mass / 10.0 mL

mass = 1.3mg/mL * 10.0 mL = 13mg

Step 3: Calculate minimum molecular weight

Molecular weight = mass of the enzyme / number of moles

Molecular weight of the enzyme = 13mg / 0.436 * 10^-3 mmol

Molecular weight = 29.82 g/mole

The minimum molecular weight of the enzyme is 29.82 g/mol