Buoyant Titration of Bovine Mercaptalbumin Chemically Modified at the Carboxyl Groups
نویسنده
چکیده
Bovine mercaptalbumin has been modified at the carboxyl groups by means of I-ethyl-3 (3-dimethylisopropyl) carbodiimide and glycine amide. A stable derivative was obtained after modification of 54 groups. The modified protein differed only slightly from the unmodified one with respect to the optical rotatory dispersion parameters ao, bo and ~. This preparation was studied in the analytical ultracentrifuge in a CsCI gradient in the pH-interval from 2 to 1 I. The buoyant densities were determined and compared with those of the unmodified protein in the same pH-interval. The contribution from the carboxyl groups to the buoyant density is discussed and compared with results obtained with other proteins and synthetic polypeptides.
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