SEDANAL

It was originally written to analyze sedimentation velocity data from heterologous interacting systems of the type

A + B = C        Ka = [C]/[A][B]

and

A + B = C        K1 = [C]/[A][B]

C + B = D        K2 = [D]/[C][B]

In its first incarnation, it was called ABCD_FITTER and when combined with ISODES_FITTER (which was devoted to analysis of isodesmic indefinite self-associating systems), it became ABCD_ISOFITTER. ABCD_ISOFITTER was designed to fit a two step binding reaction with isodesmic self association of component B as a side reaction.

These programs were combined and a data preprocessor with a GUI (graphical user interface) added and it was renamed SEDANAL.

Since those early days (1997-2000), SEDANAL has evolved to be able to handle any arbitrary reaction scheme with up to 28 components and/or 28 species related by up to 27 chemical reactions.

Both isodesmic and isoenthalpic indefinite self-associations are also included.

A Model Editor program is used to maintain a small database of models that are used by the main SEDANAL fitting program.

SEDANAL can process both sedimentation velocity and sedimentation equilibrium data.

• Sedimentation velocity
  • Fitting with the Lamm equation
• Sedimentation equilibrium
  • Fitting to sums of exponentials

Two other programs have been included within SEDANAL:

• DCDT, for the model independent analysis of sedimentation velocity data.
  • DCDT processes sedimentation velocity data using the time derviative to eliminate systematic noise and produces a plot of the concentration gradient with respect to the radial axis expressed in svedbergs. The DCDT plot [g(s*) vs s*] represents a snapshot of the sedimentation process at a particular time. It preserves diffusion information allowing accurate estimation of diffusion coefficients and, therefore, calculation of molar masses.
  • Advantages of g(s*) from dc/dt
    • The DCDT plot [g(s*) vs s*] represents a snapshot of the boundary at a particular time.
    • Uses a narrow time interval.
    • Boundary shape is preserved.
    • Diffusional information is preserved allowing accuate estimates of diffusion coefficients - even for multiple overlapping boundaries - and, therefore, reliable calculation of molar masses.
    • Boundary spreading characteristics of interacting systems are also preserved.

• BIOSPIN, for the model independent analysis of sedimentation equilibrium data.
  • BIOSPIN processes sedimentation equilibrium data to produces plots of the number, weight and z-average molar masses as a function of local cell radius and concentration.