CATALYSIS WITH MAXIMAL RATE ENHANCEMENT.

We show that polyamines specifically enhance the synth­ theses of "correct"aminoacyl tRNAs (~. ~., using the p~finyl­ alanine:tRNA ligase of yeast, one synthesizes Phe-tRNA e) and specifically inhibit the possible misacylations such as Tyr Phe-tRNA that are encouraged by the commonly used high magnesium reaction conditions. We relate this enhancement of rate and precision to current proposals on the mechanisms of enzymic catalysis and extend the concept to the certainty that some of the pre-transition state "strain" in the enzyme· substrate complex is in the form of uniquely structured water associated with the enzyme. Release of this structured water during the transition state contributes high positive entropy of activation which lowers the free energy of the transition state, thereby enhancing catalysis.