Intragenomic enzyme complements

Researchers in applied biocatalysis are now reaping the rewards of intensive effort and technological developments in the sequencing of the genomes of microbial and plant species. The genomic resource contains the sequences of millions of new genes with potential application in industrial biotechnology and includes families of enzymes within discrete genomes that potentially catalyze equivalent chemical reactions. One of the key emerging characteristics of these intragenomic complements of enzymes is the impressive breadth of catalytic diversity that is observed within them. This diversity may have been acquired either in order to combat the spectrum of metabolic challenges with which the organism may be presented in its natural environment or as part of the biosynthetic machinery evolved to produce a spectrum of secondary metabolites that will prove to be advantageous in establishing a niche. Attempts have been made to functionally characterize the intragenomic complements of enzyme families catalyzing diverse reactions including carbonyl reduction, ester hydrolysis and Baeyer–Villiger oxidation, in Gram-positive bacteria, yeasts, filamentous fungi and the plant Arabidopsis thaliana. These studies are beginning to describe in detail for the first time the impressive range of catalytic potential within single organisms for attributes such as substrate range, enantioselectivity or thermostability, each of which is of interest from an enzyme discovery perspective.