A dual functional peptide carrying in vitro selected catalytic and binding activities.

When minimal functional sequences are used, it is possible to integrate multiple functions on a single peptide chain, like a "single stroke drawing". Here a dual functional peptide was designed by combining in vitro selected catalytic and binding activities. For catalytic activity, we performed in vitro selection for a peptide aptamer binding to hemin by using ribosome display and isolated a peptide that had peroxidase activity in the presence of hemin.

Stabilized ribosome display for in vitro selection.

Ribosome display is a very effective and powerful technology for screening functional peptides or polypeptides in vitro. In ribosome display, each peptide or polypeptide (phenotype) links with its corresponding mRNA (genotype) through a ribosome. This link can be achieved by the absence of a stop codon in the mRNA, therefore stalling the ribosome at the end of translation with the nascent random sequence peptide extended by a spacer outside of the ribosome tunnel.

PEGylated antibody in organic media.

Antibodies were covalently conjugated with poly(ethylene glycol) (PEG) and the properties of the PEGylated antibodies in organic media were investigated. Two types of monoclonal antibody were used in this study. One was a monoclonal antibody (abzyme) that was prepared against a hapten mimicking a transition state of hydrolysis.