Ultracentrifugation of hypophyseal growth hormone.

Sedimentation velocity was measured in a Spinco ultracentrifuge’ operating at 165,000 X g. The hormone solutions (0.5 per cent) were prepared with borate buffer of pH 9.7 or saline at pH 9.1. Table I presents a typical run in a borate buffer; the sedimentation velocity constant was calculated by the procedure described by Svedberg and Pedersen (3). It may be noted that the individual values of szo calculated at 1920 second intervals agree to within 3 per cent. The Svensson schlieren diagrams shown in Fig. 1 indicate that the hormone is essentially monodisperse. As shown in Table II, the average sedimentation constant, corrected as