(Solved):  (will thumbs up!) Angiogenin, an enzyme involved in the formation of blood vessels, was treat ...

 (will thumbs up!)

Angiogenin, an enzyme involved in the formation of blood vessels, was treated with bromoacetate \( \left(\mathrm{BrCH}_{2} \mathrm{COO}^{-}\right. \)). An essential histidine was modified and the activity of the enzyme was reduced by 95\%. The chemical reaction for the modification of the histidine side chain with bromoacetate is shown below. Why would such a modification inactivate an enzyme that requires a His side chain for activity? His residues are often involved in proton transfer. The modified His residue results in steric hinderance. The modified His residue is positively charged. None of the above.