A solubility analysis of crystalline ox-liver catalase.

Sedimentation. This was observed in a Svedberg oilturbine ultracentrifuge by the method of Cecil & Ogston (1948). The hydrochlorides were dissolved in 0-2M-NaCI to a concentration of 1 g./100 ml. Owing to the relatively small molecular weights and high diffusion coefficients, clear sedimentation boundaries were not obtained; the sedimentation constants were therefore measured bythe method ofGutfreund& Ogston (1949). Theseresultsareprobablynot more accurate than ±5%. Diffu8ion. This was measured in the Gouy diffusiometer (Coulson, Cox, Ogston & Philpot, 1948). The same solutions were used as for sedimentation. Since an equilibrium diffusate could not be prepared by dialysis, the solvent into which diffision took place was NaCl of a concentration calculated to equal that ofdiffusate on the basis ofthe GibbsDonnan equilibrium. The observed diffusion coefficients are then comparable with the sedimentation constants. Both sedimentation and diffusion constants are corrected to their values in water at 20° (Table 1). In calculating the molecular weights, a value of 0*75 has been assumed for the partial specific volume.