Activity-Based Metaproteomics Driven Discovery and Enzymological Characterization of Novel α-Galactosidases in the Gut Microbiome

The gut microbiota is an essential contributor to human health and disease and offers an extensive resource of enzymes. Although functional metagenomics methods could predict a correlation between enzyme abundance and functional activity, many enzymes in the microbiome still remain uncharacterized. To discover the differing activities between similar annotated proteins in microbiome, approaches capable of detecting biochemical activity with identification of responsible microbes and enzymes are needed. α-Galactosidases (AGALs) are abundant in the host gut microbiota for hydrolysis of galactooligosaccharides, galactose-containing polysaccharides and glycoconjugates, and have multiple biotechnological applications with increasing demand of global AGAL market, such as food ingredients, animal feed, and biomedical sectors. However, many gut microbial AGALs still lack functional biochemical identification, which limits their usage in industrial and therapeutic applications.