Computer-assisted mathematical analysis of sigmoid biological events

A program in BASIC is described which allows accurate quantification of some numerical parameters that can be objectively correlated to biological indexes in sigmoid biological events. Attention was focused on the polymerization process of actin (a muscle protein with a mol. wt of 42,000 daltons) studied as the variation in the OD360 index with time. The experimental points, if plotted, can be well approximated by a rational function of the type delta OD360 = f(t), which passes through the origin and can be represented graphically by a sigmoid curve. The program was very helpful in comparing the experimental curves and in analysing significant parameters, such as maximum velocity and asymptote, that characterize these curves and whose interpretation would otherwise be purely subjective.