Chapter 1 - Carbohydrates and Carbohydrate-Active enZymes (CAZyme): An overview

Abstract

In the carbon cycle, a vast array of polysaccharides is enzymatically recycled through a highly complex process that generates simple sugars that are used as the main energy source by microbes. Recycling of organic compounds is heavily dependent on the carbohydrate active enzymes, popularly known as CAZymes, which deconstruct polysaccharides through a variety of elegant mechanisms, primarily such as biosynthesis and hydrolysis of glycosidic bond, beta-elimination, and removal of ester-bond. The main CAZymes are glycoside hydrolase, glycosyltransferase, polysaccharide lyase, carbohydrate esterase, and others like auxiliary activities. In general, CAZymes are modular enzymes being appended to noncatalytic carbohydrate-binding modules, which play important roles in polysaccharide recognition thus promoting an efficient catalysis. CAZymes are found in every form of life and act either as independent enzyme system or organized in high molecular mass multienzyme complexes known as cellulosomes. CAZymes have been classified into different families of functional importance based on their primary sequence homology. This chapter will give an overview of CAZymes and their role regarding carbohydrate deconstructions.