[Kinetics of the reactions joining DNA fragments, catalyzed by DNA-ligase. II. Heterogeneous mixture of fragments. Optimization of the reaction conditions].

The system of kinetic equations was proposed describing the joining of heterogeneous DNA fragments by DNA-ligase. The DNA fragments were considered as flexible rods and characterized only by molecular weights and concentrations. The program for calculating the concentrations of all circular and linear DNA forms is described. The program has been written in FORTRAN IV and calculations were made with EC 10--10. For the maximal yield of the multimeric circular DNA molecules it is recommended to begin the ligation at a high DNA concentration and then after a certain fixed time to dilute the reaction mixture. The optimum time intervals and ratios of fragment concentrations were calculated. The yield of different ligation products has been determined. The calculations of optimum reaction conditions were carried out for the construction of hybrid molecules containing DNA fragments with or without selective genetic markers.