Glycoside Hydrolase Family 121

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: ^^^Kiyotaka Fujita^^^
• Responsible Curator: ^^^Shinya Fushinobu^^^

---

Glycoside Hydrolase Family GH121
Clan	GH-x
Mechanism	retaining
Active site residues	not known
CAZy DB link
https://www.cazy.org/GH121.html

Substrate specificities

This family of glycoside hydrolases contains β-L-arabinobiosidase, which was recently established for HypBA2 from Bifidobacterium longum JCM 1217[1]. HypBA2 liberated Arafβ1-2Araf (β-Ara₂) from unmodified Arafβ1-2Arafβ1-2Arafβ-hydroxyproline (Ara₃-Hyp) but not Arafα1-3Arafβ1-2Arafβ1-2Arafβ-Hyp (Ara₄-Hyp) or Arafβ1-2Arafβ-Hyp (Ara₂-Hyp). HypBA2 directly liberated β-Ara₂ from hydroxyproline-rich glycoproteins (HRGPs) such as carrot extensin and potato lectin.

Kinetics and Mechanism

HypBA2 is a retaining enzyme. The stereochemical course of the reaction was shown by transglycosylation activity toward 1-alkanols, and following ¹H-NMR and ¹³C-NMR analysis of the methanol-adducted transglycosylation product.

Catalytic Residues

Not known.

Three-dimensional structures

Not known.

Family Firsts

First stereochemistry determination

This was determined with HypBA2 enzyme by measurement of glycosyl transfer reactions to methanol and the ¹H-NMR and ¹³C-NMR spectra.

First catalytic nucleophile identification

No experimental proof.

First general acid/base residue identification

No experimental proof.

First 3-D structure

Not known.

References

1. Fujita K, Sakamoto S, Ono Y, Wakao M, Suda Y, Kitahara K, and Suganuma T. (2011). Molecular cloning and characterization of a beta-L-Arabinobiosidase in Bifidobacterium longum that belongs to a novel glycoside hydrolase family. J Biol Chem. 2011;286(7):5143-50. DOI:10.1074/jbc.M110.190512 |