title: Rotational relaxation of free and protease-bound alpha2-macroglobulin.
abstract: The recently described triplet probe depolarization technique has been utilized to investigated the rotational relaxation of free and protease-bound alpha2-macroglobulin. The molecular Stokes radius of the free globulin was found to be 88 A, a value which, when compared to the dry radius, indicates a high degree of hydration. The correlation time of alpha2-macroglobulin does not change after its binding with chymotrypsin, but slightly increases in the presence of plasmin. In the presence of 4 M urea, alpha2-macroglobulin dissociates into subunits and this dissociation does not lead to a release of the bound proteases.
mesh_terms: D002918:Chymotrypsin; D005341:Fibrinolysin; D006801:Humans; D011485:Protein Binding; D011487:Protein Conformation; D013053:Spectrophotometry; D000511:alpha-Macroglobulins
chemical_list: D000511:alpha-Macroglobulins; D002918:Chymotrypsin; D005341:Fibrinolysin