Thio reduction of human 2 -macroglobulin. The subunit structure.

ABSTRACT: 1. Human alpha(2)-macroglobulin was prepared from a fraction obtained during the large-scale separation of normal human plasma proteins for clinical use. 2. Sedimentation-equilibrium measurements indicated a molecular weight of 725000. A value of 18.1S was obtained for s(0) (20,w). 3. The dissociation that occurs in the pH range 4.5-2.5 and in the region of neutrality in urea-containing solutions is consistent with a dimeric structure of the molecule. 4. The effects of the thiol reagents mercaptoethanol, mercaptoethylamine and N-acetylcysteine were investigated over a range of experimental conditions. Distinct components having sedimentation coefficients of 15, 12 and 8.5S were identified. 5. Conditions were found under which limited reduction with thiol liberated a subunit with a molecular weight approximately one-quarter of that of the intact molecule. This subunit retains the serological specificity of the whole molecule.

SUBMITTER: Jones JM 

PROVIDER: S-EPMC1178573 | biostudies-other | 1972 Mar

REPOSITORIES: biostudies-other