Recent advances in enzyme promiscuity

Enzyme promiscuity is defined as the capability of an enzyme to catalyze a reaction other than the reaction for which it has been specialized. Although, enzyme is known for its specificity, many enzymes are reported to be promiscuous in nature. However, the promiscuous function may not be relevant in physiological conditions. The reasons could be either very low level of catalytic activity or unavailability of the substrates in the cell. Hitherto, the enzyme promiscuity is of great importance because they are the starting point for the evolution of new functions in the nature. In addition, the promiscuous activities are utilized for the development of new catalytic functions by applying directed laboratory evolution and protein engineering techniques. The aim of this review is to provide recent developments on the understanding of the mechanism of catalytic promiscuity, evolvability of promiscuous functions and the applications of enzyme promiscuity in the designing of enhanced or new functional biocatalysts.