Phage-displayed peptide library screening for preferred human substrate peptide sequences for transglutaminase 7.

Transglutaminases are a family of enzymes that catalyze cross-linking reactions between proteins. Among the members, there is currently no information regarding the substrate preferences of transglutaminase 7 (TG7), that would clarify its physiological significance. We previously obtained several highly reactive substrate peptide sequences of transglutaminases from a random peptide library. In this study, we screened for preferred substrate sequences for TG7 from a phage-displayed 12-mer peptide library. The most preferred sequence was selected based on reactivity and isozyme specificity. We firstly exhibited the tendency for the preference of substrate sequence for TG7. Then, using the most efficient peptide, Z3S, we established an in vitro assay system to assess enzymatic activity of TG7.