Crosslinking and labeling of membrane proteins by transglutaminase-catalyzed reactions.

Transglutaminase enzymes catalyze for the formation of epsilon(gamma-glutamyl)lysyl crosslinks, or the substitution of a variety of primary amines for the amide function of protein-bound glutaminyl residues. These enzymes should therefore be useful in crosslinking the proteins of membranes and in attaching a variety of chemical probes and labels to these proteins. This usefulness is demonstrated in experiments with the enzyme liver transglutaminase and the membranes with the enzyme liver transglutaminase and the membranes of mouse erythrocytes and of rabbit skeletal muscle sarcoplasmic reticulum.