Question

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 3.4 mg/mL of a pure enzyme, an investigator added just enough AgNO3 to completely inactivate the enzyme. A total of 0.134 μmol AgNO3 was required. Calculate the minimum molecular weight (????r) of the enzyme.

Answer 1

Step-by-step explanation:

one mole of AgNO₃ reacts to inactivate one mole of enzyme

mg of enzyme in 10 mL = 3.4 x 10 mg = 34 mg .

required AgNO₃ = .134 x 10⁻⁶ mole

.134 x 10⁻⁶ mole AgNO₃ is required for inactivating 34 mg of enzyme

1 mole of AgNO₃ will be required for inactivating 34 / (.134 x 10⁻⁶ ) mg of enzyme

= 253.73 x 10⁶ mg of enzyme

= 253.73 x 10³ g of enzyme

Mol weight of enzyme = 253.73 x 10³ .