J. Biol. Chem., Vol. 261, Issue 18, 8122-8127, 06, 1986
Cellular transglutaminase. Lung matrix-associated transglutaminase: characterization and activation with sulfhydryls
ET Cocuzzi and SI Chung
Transglutaminase in the rat lung is tightly associated with the insoluble
matrix which is not extractable with detergent, 0.5 M NaCl, and 40%
glycerol solutions. The insoluble matrix was found to be rich in heparin
sulfate and poor in collagen, elastin, and DNA. The lung transglutaminase
was found to be distinct from tissue transglutaminase (identifiable with
the well-characterized guinea pig liver transglutaminase) in its retention
volume in DEAE-Sephacel columns and its Kd value in gel-filtration columns.
The enzyme was activated 6-8- fold with the sulfhydryl reagent
dithiothreitol. This activation was accompanied with the dissociation of
enzyme from the tightly bound insoluble matrix and resulted in changes of
the molecular properties of the enzyme--increase in affinity for
anion-exchanger and decrease in Stokes radius. Addition of 50 mM KSCN
induced a 2-fold increase in SH- dependent activation of transglutaminase
activity. These results suggest that sulfhydryl agents may play a role in
the activation and compartmental translocation of the transglutaminase in
the lung.