[H-3]-LABELED FUCOSE INCORPORATION BY HEALING SKIN WOUNDS AND THE EFFECTS OF TRANSGLUTAMINASE INHIBITORS

Punch wounds (3 mm) were made in the skin of rats and the animals were killed after 1 or 3 days. Plugs (4 mm) of wounded and unwounded skin were incubated in vitro with [3H]fucose. The labeled plugs were homogenized and subjected to sequential extraction with buffered salt solutions, ethanol-ether, and 8 M urea-50 mM dithiothreitol (DTT). Nondialyzable counts in the extracts and insoluble residue were determined and the incorporation of label by wounded and unwounded skin plugs was compared. Wound plugs showed a greater total incorporation of [3H]fucose. A greater proportion of [3H]fucose was found in the urea-DTT extracts. The highest specific activity (dpm [3H]fucose/mg dry wt) was found in a finely dispersed precipitate, sedimenting at 10,000 .times. g but not at 1000 .times. g. The transglutaminase inhibitors aminoacetonitrile and dansyl cadaverine increased the extractability of a portion of the material which incorporated [3H]fucose without affecting the total incorporation. Evidently, healing wounds have an increased biosynthetic capacity for an insoluble fucosylated glycoprotein fraction and transglutaminase is necessary to make this fraction fully insoluble.