Glycoside Hydrolase Family 114

• Author: ^^^Spencer Williams^^^
• Responsible Curator: ^^^Spencer Williams^^^

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Glycoside Hydrolase Family GH114
Clan	none
Mechanism	probably retaining
Active site residues	not known
CAZy DB link
http://www.cazy.org/GH114.html

Substrate specificities

Only a single enzyme of glycoside hydrolase family 114 has been characterized; an endo α-1,4-polygalactosaminidase from Pseudomonas sp. 881 [1]. This enzyme hydrolyzes α-1,4-polygalactosamine to oligosaccharides in an endo-acting manner. α-1,4-Polygalactosamine, also known as galactosaminoglycan, is a polymer consisting of α-1,4-linked galactosamine residues, which is only partially N-acetylated, and may also contain N-formyl residues, and is produced by a range of fungi including Aspergillus parasiticus, Paecilomyces sp. I-1, and Neurospora crassa. An endogalactosaminidase has been purified from Streptomyces griseus; the sequence of this protein is unknown [2].

Kinetics and Mechanism

The endo α-1,4-polygalactosaminidase from Pseudomonas sp. 881 possesses activity on deacetylated α-1,4-polygalactosamine, but no activity on fully N-acetylated α-1,4-polygalactosamine. Tetraose and longer galactosamine oligosaccharides were hydrolyzed to galactosaminobiose and galactosaminotriose as the final products [3]. The enzyme is inhibited by

Catalytic Residues

None known.

Three-dimensional structures

No 3-D structure has been reported for any member of this family.

Family Firsts

First stereochemistry determination

Not known, but a retaining mechanism may be inferred from report of transglycosylation activity [3].

First catalytic nucleophile identification

Not known.

First general acid/base residue identification

Not known.

First 3-D structure

None reported.

References

1. Tamura, J.-I., Hasegawa, K., Kadowaki, K., Igarashi, Y., Kodama, T. Molecular Cloning and Sequence Analysis of the Gene Encoding an Endo a-l,4 Polygalactosaminidase of Pseudomonas sp. 881. J. Fermentation Bioengineer., 1995, 80, 305. [1].

2. Reissig JL, Lai WH, and Glasgow JE. (1975). An endogalactosaminidase from Streptomyces griseus. Can J Biochem. 1975;53(12):1237-49. DOI:10.1139/o75-169 |
3. Tamura J, Abe T, Hasegawa K, and Kadowaki K. (1992). The Mode of Action of Endo α-1,4 Polygalactosaminidase from Pseudomonas sp. 881 on Galactosaminooligosaccharides. Biosci Biotechnol Biochem. 1992;56(3):380-3. DOI:10.1271/bbb.56.380 |