ULTRACENTRIFUGAL CHARACTERISTICS OF HUMAN, MONEKY AND RAT TRANSFERRINS

Abstract

Human, monkey and rat transferrins have been studied in the ultracentrifuge at high speed to measure sedimentation coefficients and at low speed to determine molecular weights. The sedimentation coefficients (and dependence on concentration) were closely similar for all species, S[image] being 5.1-5.2s, but rather lower than the values available for human '' and pig transferrins. This difference may be due partly to temperature errors in some of the older work, but there is a residual, fairly small, discrepancy difficult to account for. The molecular weights of all three transferrins were close to 68,000, in comparison with previous values of about 90,000 for human and pig transferrins. The reasons for this are discussed.