Ser-His catalyses the formation of peptides and PNAs.
Gorlero M, Wieczorek R, Adamala K, Giorgi A, Schininà ME, >Stano P, Luisi PL.
FEBS Lett. 2009 Jan 5;583(1):153-6. Epub 2008 Dec 9

The dipeptide seryl-histidine (Ser-His) catalyses the condensation of esters of amino acids, peptide fragments, and peptide nucleic acid (PNA) building blocks, bringing to the formation of peptide bonds. Di-, tri- or tetra-peptides can be formed with yields that vary from 0.5% to 60% depending on the nature of the substrate and on the conditions. Other simpler peptides as Gly-Gly, or Gly-Gly-Gly are also effective, although less efficiently. We discuss the results from the viewpoint of primitive chemistry and the origin of long macromolecules by stepwise fragment condensations.