“…The preference of this mechanism is predetermined by the unfavourable free energy change for the formation of these bonds from unactivated reagents in neutral aqueous solution (Carpenter,1960;Petkov,1982).Presently it is a subject of intensive studies in the case of enzymic peptide bond synthesis (Gololobov et ai.,1989;Kasche,1989;Schellenberger et ai.,1990;Stoineva et ai.,1990). Although widely used in genetic engineering and molecular biology (Davies et al,1983;Knorre et ai.,1985), the kinetically-controlled enzymic synthesis of nucleotides in vitro is not even identified as such a mechanism. In the present paper we report the basic parameters of the kinetically-controlled accumulation of diribonucleoside phosphates during the ribonuclease A-catalyzed alcoholysis of 2':3'-cyclic nucleoside phosphates.…”