Open AccessTransglutaminase‐sensitive glutamine residues of human plasma fibronectin reveled by studying its proteolytic fragments
Author(s) -
FESUS Laszlo,
METSIS Madis L.,
MUSZBEK Laszlo,
KOTELIANSKY Victor E.
Publication year - 1986
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1986.tb09407.x
Subject(s) - tissue transglutaminase , glutamine , fibronectin , proteolytic enzymes , chemistry , human plasma , biochemistry , enzyme , amino acid , chromatography , extracellular matrix
The sites of transglutamination of fibronectin and fibronectin fragments, by coagulation factor XIIIa and tissue transglutaminase, were studied. It was shown that the intact fibronectin molecule has two sites sensitive to coagulation factor XIIIa and four sites sensitive to tissue transglutaminase: 180–190–kDa gelatin/heparin‐binding fragments, 2 and 5–6 sites; 29–kDa heparin‐I/fibrin‐I‐binding N‐terminal fragments, 1 and 2 sites; 70‐kDa gelatin‐binding fragments, 0 and 1 site; 60‐kDa cell‐binding central fragments, 1 and 3–4 sites; 60–kDa, 45–kDa, 30–kDa heparin‐II‐binding C‐terminal fragments, 1 and 2 sites. Thus, we have found a new coagulation‐factor‐XIIIa‐sensitive site localized in the cell‐binding central fragment, inaccessible to enzyme in the intact fibronectin molecule. Tissue transglutaminase appeared to interact with all of the three coagulation‐factor‐XIIIa‐sensitive‐sites and, in addition. some others which are either available on the intact molecule or can be revealed only in proteolytic fragments of the fibronectin. We suggest that interdomain and intersubunit interactions in the intact fibronectin molecule account for the masking of glutamine residues potentially accessible to transglutaminases.