Effect of methylamine and plasmin on the conformation of human alpha 2-macroglobulin as revealed by differential scanning calorimetric analysis.

Journal Article (Journal Article)

Differential scanning calorimetric analysis was used as a probe of the conformational alteration in human alpha 2-macroglobulin (AM) upon its complex formation with methylamine and with the protease, human plasmin. The slow electrophoretic form of AM displayed a single thermal transition, characterized by a temperature midpoint (Tm) of 65.8 +/- 0.3 degrees, a calorimetric enthalpy (delta Hc) of 2,550 +/- 150 kcal/mol and a van't Hoff enthalpy (delta Hvh) of 140 kcal/mol. In the presence of sufficient methylamine to irreversibly disrupt the four thiol ester bonds in AM, a single thermal transition was obtained, characterized by a Tm of 62.8 +/- 0.3 degrees, a delta Hc of 1,700 +/- 100 kcal/mol, and a delta Hvh of 169 kcal/mol. These data suggest that a major conformational alteration is produced in AM upon complex formation with methylamine. When plasmin interacts with AM, the resulting thermogram displays Tm values for AM of 68-69 degrees and 77 degrees, also suggestive of a large conformational alteration in AM. However, this latter alteration appears dissimilar to the change induced by methylamine.

Full Text

Duke Authors

Cited Authors

  • Cummings, HS; Pizzo, SV; Strickland, DK; Castellino, FJ

Published Date

  • April 1984

Published In

Volume / Issue

  • 45 / 4

Start / End Page

  • 721 - 724

PubMed ID

  • 6202335

Pubmed Central ID

  • PMC1434896

International Standard Serial Number (ISSN)

  • 0006-3495

Digital Object Identifier (DOI)

  • 10.1016/S0006-3495(84)84214-9


  • eng

Conference Location

  • United States