Details

Autor(en) / Beteiligte

• Wallace, Donald G.
• Donovan, John W.
• Schneider, Phillip M.
• Meunier, Ann M.
• Lundblad, John L.

Titel

Biological activity and conformational stability of the domains of plasma fibronectin

Ist Teil von

• Archives of biochemistry and biophysics, 1981-12, Vol.212 (2), p.515-524

Ort / Verlag

United States: Elsevier Inc

Erscheinungsjahr

1981

Quelle

Elsevier Journal Backfiles on ScienceDirect (DFG Nationallizenzen)

Beschreibungen/Notizen

• As measured by two assays of biological activity, fibronectin was readily denatured by heat. Both by the rat liver slice assay and by gelatin-latex agglutination, 90% of the activity disappeared in about 10 min at 60 °C. In contrast, immunological activity, as measured by microcomplement fixation, showed little change at 10 min and was at least 60% as great as unheated fibronectin after 20–50 min at 60 °C. Binding of heparin was unaffected by heating up to 52 min, but at very long times (48 hr at 60 °C), it also was lost. Differential scanning calorimetry of native fibronectin showed three endothermal denaturing transitions, at 68, 82, and 119 °C. Enthalpies of denaturation for the three transitions are approximately 2.6, 0.4, and 0.7 cal/g of flbronectin. These results are consistent with a three-domain structure for fibronectin. The domain which unfolds at 68 °C is associated with gelatin binding and cell. binding. The 82 °C domain appears to be associated with much of the immunological activity, and the 119 °C domain with heparin binding, as well as with some immunological activity. Residual immunological activity after loss of heparin binding may reside in nonordered portions of the molecule.