CESA_like is the cellulose synthase superfamily. The cellulose synthase (CESA) superfamily includes a wide variety of glycosyltransferase family 2 enzymes that share the common characteristic of catalyzing the elongation of polysaccharide chains. The members include cellulose synthase catalytic subunit, chitin synthase, glucan biosynthesis protein and other families of CESA-like proteins. Cellulose synthase catalyzes the polymerization reaction of cellulose, an aggregate of unbranched polymers of beta-1,4-linked glucose residues in plants, most algae, some bacteria and fungi, and even some animals. In bacteria, algae and lower eukaryotes, there is a second unrelated type of cellulose synthase (Type II), which produces acylated cellulose, a derivative of cellulose. Chitin synthase catalyzes the incorporation of GlcNAc from substrate UDP-GlcNAc into chitin, which is a linear homopolymer of beta-(1,4)-linked GlcNAc residues and Glucan Biosynthesis protein catalyzes the elongation of beta-1,2 polyglucose chains of Glucan.
Hyaluronan synthases catalyze polymerization of hyaluronan. Hyaluronan synthases (HASs) are bi-functional glycosyltransferases that catalyze polymerization of hyaluronan. HASs transfer both GlcUA and GlcNAc in beta-(1,3) and beta-(1,4) linkages, respectively to the hyaluronan chain using UDP-GlcNAc and UDP-GlcUA as substrates. HA is made as a free glycan, not attached to a protein or lipid. HASs do not need a primer for HA synthesis; they initiate HA biosynthesis de novo with only UDP-GlcNAc, UDP-GlcUA, and Mg2+. Hyaluronan (HA) is a linear heteropolysaccharide composed of (1-3)-linked beta-D-GlcUA-beta-D-GlcNAc disaccharide repeats. It can be found in vertebrates and a few microbes and is typically on the cell surface or in the extracellular space, but is also found inside mammalian cells. Hyaluronan has several physiochemical and biological functions such as space filling, lubrication, and providing a hydrated matrix through which cells can migrate.