A free derivative program for non-linear regression analysis of enzyme kinetics to be used on small computers

A non-linear regression program, written in BASIC, is described. The program uses the Marquardt 's algorithm as modified by Reich et al. (Eur. J. Biochem., 26 (1972) pp. 368-379). The user only supplies the expression to fit, since the program uses numerical differentiation. It is possible to fit models of 1 substrate, 2 substrates, 1 substrate and 1 inhibitor, and 2 substrates and 1 inhibitor. Likewise, several weighting patterns, as well as a simple or robust regression, can be selected.