IUBMB Enzyme Nomenclature


Accepted name: xyloglucan-specific endo-processive β-1,4-glucanase

Reaction: Hydrolysis of (1→4)-D-glucosidic linkages in xyloglucans so as to successively remove oligosaccharides from the newly-formed chain end after endo-initiation on a polymer molecule

Other name(s): Cel74A; [(1→6)-α-D-xylo]-(1→4)-β-D-glucan exo-glucohydrolase (ambiguous); xyloglucan-specific exo-β-1,4-glucanase (ambiguous)

Systematic name: [(1→6)-α-D-xylo]-(1→4)-β-D-glucan endo-processive glucohydrolase

Comments: The enzyme removes branched oligosaccharides, containing preferentially four glucoside residues in the main chain, from xyloglucan molecules in a processive manner after the initial endo-type attack on a polysaccharide [1-5]. Hydrolysis occurs at either the unsubstituted D-glucopyranose residue in the main backbone and/or the D-glucopyranose residue bearing a xylosyl group [1-5]. The enzyme does not display activity, or shows very low activity, towards other β-D-glucans [1,2,4,5].

Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 1000598-79-7


1. Grishutin, S.G., Gusakov, A.V., Markov, A.V., Ustinov, B.B., Semenova, M.V. and Sinitsyn, A.P. Specific xyloglucanases as a new class of polysaccharide-degrading enzymes. Biochim. Biophys. Acta 1674 (2004) 268-281. [PMID: 15541296]

2. Ichinose, H., Araki, Y., Michikawa, M., Harazono, K., Yaoi, K., Karita, S. and Kaneko, S. Characterization of an endo-processive-type xyloglucanase having a β-1,4-glucan-binding module and an endo-type xyloglucanase from Streptomyces avermitilis. Appl. Environ. Microbiol. 78 (2012) 7939-7945. [PMID: 22941084]

3. Matsuzawa, T., Saito, Y. and Yaoi, K. Key amino acid residues for the endo-processive activity of GH74 xyloglucanase. FEBS Lett. 588 (2014) 1731-1738. [PMID: 24657616]

4. Arnal, G., Stogios, P.J., Asohan, J., Skarina, T., Savchenko, A. and Brumer, H. Structural enzymology reveals the molecular basis of substrate regiospecificity and processivity of an exemplar bacterial glycoside hydrolase family 74 endo-xyloglucanase. Biochem. J. 475 (2018) 3963-3978. [PMID: 30463871]

5. Arnal, G., Stogios, P.J., Asohan, J., Attia, M.A., Skarina, T., Viborg, A.H., Henrissat, B., Savchenko, A. and Brumer, H. Substrate specificity, regiospecificity, and processivity in glycoside hydrolase family 74. J. Biol. Chem. 294 (2019) 13233-13247. [PMID: 31324716]

6. Gusakov, A.V. Additional sequence and structural characterization of an endo-processive GH74 xyloglucanase from Myceliophthora thermophila and the revision of the EC entry. Biochim. Biophys. Acta. 1864 (2020) 129511. [PMID: 31911243]

[EC created 2005, withdrawn at public-review stage, modified and reinstated 2006, modified 2020]

Return to EC 3.2.1 home page
Return to EC 3.2 home page
Return to EC 3 home page
Return to Enzymes home page
Return to IUBMB Biochemical Nomenclature home page