PLP-dependent Enzymes as Important Biocatalysts for the Pharmaceutical and Chemical Industries
Enzymes catalyze a plethora of chemical reactions in nature. These biocatalysts offer a variety of benefits that no other synthetic catalyst can offer: high catalytic power, regio- and stereo-selectivity, ability to work at mild conditions, and to react in environmentally friendly manufacturing processes. However, enzymes are not normally optimally suited for industrial applications. It is important to improve their properties to favor a more efficient application of enzymes in an industrial setting while also expanding the range of potential chemical reactions that they can catalyze. Problems like the scarce nature of oil reserves, together with increasing concerns on man-made environmental damage, have led to a boost in the need for the development and optimization of new and improved tailor-made enzymes for industrial applications. In this review, we focus our analysis on different enzymes, containing a pyridoxal-5’-phosphate (PLP) cofactor, that have great potential as biocatalysts in a variety of industries and applications. The selected PLP enzymes are the ω-transaminases, lysine decarboxylase, threonine aldolase, L-tyrosine phenol-lyase, α-amino-ϵ-caprolactam racemases, and cystathionine β-lyases. For each of these enzymes, the catalytic mechanism, industrial application, as well as, the advantages and disadvantages of their application is reviewed in detail. In general, this review highlights the immense biocatalytic potential, rich chemistry and diverse set of applications that different enzymes sharing a common element (PLP) can have.