Use recombinant dna methods to prepare a mutant

A drug company decided to use recombinant DNA methods to prepare a mutant

a1-antiproteinase (also sometimes referred to by its old name, a1-antitrypsin) that would be moreresistant to oxidation than the naturally occurring inhibitor, to administer intravenously to emphysemapatients. What single amino acid substitution would you recommend, and why?

"Is this question part of your assignment? We can help"