Mutagenesis and Selection for Protein Engineering - Mutagenesis and selection can be effectively utilized for improving a specific property of an enzyme. Following are some of the examples of selection of mutant enzymes:

(i) E. coli anthranilate synthetase enzyme is normally sensitive to tryptophan inhibition due to feedback inhibition. An MTR 2 mutation of E. coli was found to possess an altered form of enzyme anthranilate synthetase that is insensitive to tryptophan inhibition. They may help in continuous synthesis of tryptophan without any inhibition by tryptophan accumulated as a product.

(ii) Xanthine dehydrogenase enzyme oxidizes 2 hydroxy-purine at position 8, but a mutant has been inolated which oxidizes 2 hydroxy-purine at position 6.