Glycoside Hydrolase Family 67

This page is currently under construction. This means that the Responsible Curator has deemed that the page's content is not quite up to CAZypedia's standards for full public consumption. All information should be considered to be under revision and may be subject to major changes.

• Author: Harry Gilbert
• Responsible Curator: Harry Gilbert

---

Glycoside Hydrolase Family GHnn
Clan	GH-x
Mechanism	retaining/inverting
Active site residues	known/not known
CAZy DB link
http://www.cazy.org/fam/GHnn.html

Substrate specificities

GH67 contains enzymes that display alpha-glucuronidase activity. The enzymes target the glucuronic acid appended to the C2-OH of the xylose at the non-reducing end of xylooligosaccharides. The enzymes display a preference for 4-O-methyl-D-glucuronic acid side chains. The length of the oligosacchride does not influence catalytic rate indicating that the enzyme only interacts with the uronic acid and the linked xylose. These enzymes do not remove glucuronic acid from internal regions of xylan (cite)#1#2(/cite). The enzymes are generally intracellular or membrane associated (cite)#3#4(/cite)suggesting that they play a terminal role in uncapping decorated xyloooligosacchrides, making these molecules available to beta-xylosidases produced by the host.

Kinetics and Mechanism

Alpha-glucuronidases hydrolyse their target glycoside bond through a single displacement acid-base assisted mechanism, and thus the released glucuronic acid released is in a beta conformation (cite)#5(/cite).

Family Firsts

First sterochemistry determination

Cite some reference here, with a short explanation [1].

First catalytic nucleophile identification

First general acid/base residue identification

First 3-D structure

References

1. Comfort DA, Bobrov KS, Ivanen DR, Shabalin KA, Harris JM, Kulminskaya AA, Brumer H, and Kelly RM. (2007). Biochemical analysis of Thermotoga maritima GH36 alpha-galactosidase (TmGalA) confirms the mechanistic commonality of clan GH-D glycoside hydrolases. Biochemistry. 2007;46(11):3319-30. DOI:10.1021/bi061521n |