K. E. Van Holde

Sedimentation in Chemically Reacting Systems. I. The Isomerization Reaction

A solution has been obtained for the differential equations describing the changes in concentrations with time and position in an ultracentrifuge cell during the sedimentation of an isomerizing substance. It is assumed that diffusion is negligable, and that the centrifugal field and cell cross section are constant. In addition to the general result, simple approximate solutions are presented for the cases where the chemical reactions are moderately slow and moderately fast, compared to the rate of separation of species by the centrifugal field.

An investigation of bacteriophage lambda, its protein ghosts and subunits.

The sedimentation coefficients and molecular weights of bacteriophage lambda and its ghost were determined as So(20,w) = 416 x 10(-13) second and M = 57 x 10(6) for the virus, and So(20,w) = 141 x 10(-13) second and M = 21 x 10(6) for the ghost. The protein portion of the virus consists of at least two distinct types of subunits, with molecular weights of 55,000 and 110,000, which differ markedly in their amino acid content.

Role of Hydrodynamic Interaction in the Diffusion of n‐Alkanes in Carbon Tetrachloride

The diffusion coefficients of a series of normal paraffins in carbon tetrachloride have been determined by the Rayleigh interferometric method. The dependence of the frictional coefficient on chain length has been examined in terms of a theory which takes into account the hydrodynamic interaction between segments of the diffusing molecule. If average intersegment distances are calculated on the basis of simple models, values for frictional coefficients are predicted which are in good agreement with the experimental results.