Peptide Ligases—Tools for Peptide Synthesis

Since the ligation of peptide fragments in vivo is meaningless , no natural enzyme is capable of replacing chemical coupling methods, which have the danger of racemization in segment condensation. Native proteases and those altered by protein design as well as catalytic antibodies may serve as peptide ligases, as demonstrated recently with subtiligase in the chemoenzymatic synthesis of R Nase A.