Polyglucuronic acids: Structures, functions and degrading enzymes

Totally unknown at the beginning of the nineties, polyglucuronic acids have aroused the interest of scientific community working with polysaccharides. These polyuronides, initially isolated from microorganisms, have been later identified in some complex cell walls such as those of green algae. The recent progresses in the regioselective oxidation of neutral glucans permits them to be obtained on a large scale under relatively mild conditions. At the same time, new enzymes able to degrade these polysaccharides have been identified leading notably to the description of a new polysaccharide lyase family. The different forms of polyglucuronic acids such as those of low molecular weight obtained after enzymatic degradation of β-(1,4)-polyglucuronic acids have been tested for biological activities with success. So, several industrial applications associated with these compounds have been patented. This review focuses on this class of polyuronides and the enzymes capable of cleaving them.