This paper presents a new procedure for the derivation of steady-state rate calculations by computer for enzyme kinetics using data on strains of human dihydrofolate reductase (DHFR) reported in the literature. This enzyme continues to command the attention of scientists since its discovery in the late 1950s in connection with applications to cancer therapy. Kinetics of nonhuman strains previously reported (Happel, J.; Sellers, P. H. J. Phys. Chem. 1995, 99, 6595) appears to be much simpler, in the present case it is necessary to introduce the concepts that an elementary step should be treated as a vector possessing the same direction in each submechanism that it occurs.