Transglutaminase 2 and Factor XIII catalyze distinct substrates in differentiating osteoblastic cell line: utility of highly reactive substrate peptides
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Differentiated osteoblastic cell line, MC3T3-E1 expresses transglutaminase 2 (TG2) and Factor XIII (FXIII). In previous studies, we identified isozyme-specific and highly reactive glutamine-donor substrate peptides (pepF11KA and pepT26) for each isozyme. Using these peptides, we compared the reaction products with lysine-donor substrates for each isozyme in differentiating MC3T3-E1 cells. By this analysis, distinct substrates for the activated TG2 and FXIII were detected in cultured cellular extract. Possible substrates that incorporated biotin-labeled peptides were further purified using streptavidin-affinity chromatography. Several isozyme-specific substrates were identified by mass spectrometry analysis of the purified fractions. These analyses also indicate the benefit of the substrate peptides for obtaining distinct substrates in a reaction mixture where two isozymes co-exist.
KeywordsTransglutaminase Osteoblast TG2 Factor XIII
l-ascorbic acid 2-phosphate
Coomassie Brilliant Blue
We greatly appreciate Dr. Masatoshi Maki and Dr. Hideki Shibata in our laboratory for providing valuable suggestions. This work was supported by a Grant-in-Aid for Scientific Research on Innovative Areas (No. 20200072) (to K. H.) from the Ministry of Education, Sports, Science and Technology (MEXT, Japan).