The behaviour of pathological sera in the ultracentrifuge

Abstract

Untreated antidiphtheria horse serum in the ultracentrifuge is shown to consist of albumin and globulin components in ca. equal concns. Most of the pathologic human sera examined contain 3 molecular fractions corresponding in sedimentation constants to the 3 fractions of normal human sera. In some cases the identity of the corresponding fractions in normal and pathologic sera is doubtful and in 2 cases the presence of entirely new substances is established, since there are 4 fractions present altogether. One of the new proteins has a molecular wt. less than that of serum albumin, and the other is intermediate between serum albumin and serum globulin. In most of the human sera examined the concns. of the heavier fractions are greater than are found in normal sera. The relative concns. of the fractions are changed by simple dilution, the change being of the same general nature as that found in normal sera. Untreated pleural exudate behaved in the ultracentrifuge like the serum from the same patient diluted to the same concn. of total protein. In 5 cases there is evidence of the presence of polydisperse protein in the serum. In 4 of these 5 cases protein was present in the urine.