Adventures in trying to understand enzymic catalysis

The complexities and marvels of enzymic catalysis will be illustrated for three cases: first, the importance of conformational flexibility in the mode of action of dihydrofolate reductase analyzed through a combined kinetic and mutagenic examination of function; second, the uniqueness of the nature and locus of active site side chains as revealed by the result of saturation mutagenesis of these amino acids in glycinamide ribonucleotide transformylase; and third, the implications for molecular recruitment in achieving enzyme function through the construction of hybrid genes from genes associated with the purine biosynthetic pathway.