MSTARA AND MSTARI - INTERACTIVE PC ALGORITHMS FOR SIMPLE, MODEL-INDEPENDENT EVALUATION OF SEDIMENTATION EQUILIBRIUM DATA

This paper describes a program available for PC's for the evaluation o f molecular weights from sedimentation equilibrium This program, in it s two forms MSTARA for absorption optical records and MSTARI for inter ference optical records - requires no prior assumption of the nature o f the system (ideal, non-ideal, monodisperse, polydisperse, self-assoc iating etc.) and takes into consideration the whole solute distributio n (i.e. from solution meniscus to cell base) in the ultracentrifuge ce ll rather than just a selected data-set. MSTARA or MSTARI are therefor e recommended as a first analysis programme of sedimentation equilibri um data coming off an absorption or interference based analytical ultr acentrifuge. These programmes are therefore particularly well suited i f heterogeneity (polydispersity or interaction phenomena) or nonideali ty is suspected. Their use is demonstrated for a series of data-set ty pes (ideal, non-ideal, polydisperse and self-associating). Although MS TARA and MSTARI are model independent, they provide the basis for more detailed analysis of interactions, polydisperse distributions or non- ideality via easy export of ASCII datafiles to model dependent routine s.