Endo-P-glucuronidases

A novel l yR]uzt n in-degradmg enzyme hns been isolated, purified, and characterized from Antarctic krill (Euphausia superba) [28]. Preliminary investigations show that the enzyme acts as an endo-p-glucuronidase. 

Organisms Containing Endo-p-glucuronidase Type Hyaluronidases... 

There are hyaluronidases that function as endo-(3-glucuronidases that cleave the (1 3)-P glycosidic bonds. However, no sequence data on these enzymes is yet available. These enzymes are characteristic of annelids such as leeches e.g., Herudo medicinalis [196-198], and certain crustaceans [199]. They utilize the hydrolysis mechanism, and thus resemble the vertebrate enzymes more closely than the prokaryotic hyaluronidases. 

The complete degradation of hemicellulose becomes more complex than that of cellulase, since substituent-hydrolyzing activities are also necessary. With heteroxylans, apart from endo-l,4- 3-xylanase, which catalyzes the hydrolysis of internal 3-l,4-xylan links and P-xylosidase, which catalyzes the hydrolysis of xylooligossacharides, mainly xylobiose into xylose, other enzymes must act to accomplish complete hydrolysis, such as acetyl xylan esterase, a-glucuronidase, and a-L-arabinofuranosidase (1). 

Unlike starch or cellulose, BSG hemicellulose has a complex structure, which is still present, in part, on its autohydrolysis products. Oligosaccharides from BSG hydrolysis consist mainly of branched arabino-xylo-glucurono oligosaccharides that are not highly acetylated when compared to other xylans, such as from Eucalyptus wood (31). The action of several enzymatic activities including endo-l,4-P-xylanase P-xylosidase and accessory activities such as acetyl xylanesterase, a-glucuronidase, and a-arabino-furanosidase is therefore required for the complete hydrolysis of OCL to monosaccharides. 

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