Figure 1.

Activity of fibronectin peptides with small numbers of glutamine residues as amine acceptors. The different peptides were incubated with 5 μCi of ¹⁴C-labeled glycine ethyl-ester for 1 h. Reaction was stopped by addition of EDTA, and the products were resolved on a gel prepared according to Swank and Munkres (25). The gel was fixed and dried, and the radioactivity incorporated in the peptide was revealed by fluorography after a 24-h exposure. Q₂ is much more active than Q₁. Q₆ is active, but most of the product did not enter the gel. The control incubated in the presence of EDTA shows no incorporation.