Glucanase

The secondary and tertiary structures of β-glucanases involves the stacking of multiple β-sheets, each of which are made of several anti-parallel strands that bend and form a cleft crossing the active site of the enzyme.[1] This type of structure has been called the "jelly roll fold."

• 1,3-β-glucanases (laminarinases, EC 3.2.1.39)[1]
• Endo-1,3(4)-β-glucanase
• β-1,3-glucanase, an enzyme in plants that breaks down β-1,3-glucans such as callose or curdlan
• β-1,6 glucanase, an enzyme that breaks down β-1,6-glucans
• Cellulase, an enzyme that perform the hydrolysis of 1,4-beta-D-glycosidic linkages in cellulose, lichenin and cereal β-D-glucans.[2]
• Xyloglucan-specific endo-beta-1,4-glucanase
• Xyloglucan-specific exo-beta-1,4-glucanase

• α-1,4-glucanase, an enzyme that breaks down α-1,4-glucans
• α-1,6-glucanase, an enzyme that breaks down α-1,6-glucans
• Pullulanase, a specific kind of glucanase that degrade pullulan

The functional formation of the enzyme-substrate complex is dictated by the induced-fit mechanism.[1]

Bacteria such as Escherichia coli, and Bacillus spp. produce 1,3-1,4-β-glucanases in order to degrade and use polysaccharides from their environment as an energy source.[1] These bacterial glucanases are an example of convergent evolution as they share similarity or relation with plant glucanase primary, secondary, or tertiary structure.[1] Glucanases have also been found to be secreted by fungi such as Trichoderma harzianum, Saccharomyces cerevisiae and the anaerobic fungi Orpinomyces and Neocallimastigomycota, found in the digestive tracts of herbivores.[1][5][6] T. harzianum is also used as a fungicide, which is linked to the ability of its β-gluanases to hydrolyze phytopathogenic fungi via a mycoparasitic attack.[6]

Barley 1,3-1,4-β-glucanases are heat inactivated during malting, which can cause the build-up of high molecular-weight glucans which in turn result in reduced extract yield, lower filtration rates, and even gelatinous precipitates in the finished product. As a remedy, heat-resistant bacterial 1,3-1,4-β-glucanases are added.[1]

Used in enological practices during the aging process of wine, particularly when aged on lees with microxygenation. The enzyme aids in autolysis of yeast cells to release polysaccharides and mannoproteins, which is believed to aid in the color and texture of the wine.

In the production of feedstuff for broiler chickens and piglets, it has been found that β-glucanases improve digestibility of barley-based diets.[1]