IUBMB Enzyme Nomenclature


Accepted name: 4,3-α-glucanotransferase

Reaction: formation of a mixed (1→4)/(1→3)-α-D-glucan from (1→4)-α-D-glucans

Other name(s): gtfB (gene name) (ambiguous)

Systematic name: (1→4)-α-D-glucan:(1→4)/(1→3)-α-D-glucan 3-α-D-glucosyltransferase

Comments: The enzyme, characterized from the bacterium Lactobacillus fermentum NCC 2970, possesses hydrolysis and transglycosylase activities on malto-oligosaccharides with a degree of polymerization of at least 6, as well as polymers such as amylose, potato starch, and amylopectin. The enzyme, which belongs to glycoside hydrolase 70 (GH70) family, attaches the glucosyl residues by α(1→3) linkages in both linear and branched orientations. While capable of forming large polymers, the enzyme produces mainly oligosaccharides in vitro.

Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number:


1. Gangoiti, J., van Leeuwen, S.S., Gerwig, G.J., Duboux, S., Vafiadi, C., Pijning, T. and Dijkhuizen, L. 4,3-α-Glucanotransferase, a novel reaction specificity in glycoside hydrolase family 70 and clan GH-H. Sci. Rep. 7 (2017) 39761. [PMID: 28059108]

2. Pijning, T., Gangoiti, J., Te Poele, E.M., Borner, T. and Dijkhuizen, L. Insights into broad-specificity starch modification from the crystal structure of Limosilactobacillus reuteri NCC 2613 4,6-α-glucanotransferase GtfB. J. Agric. Food Chem. 69 (2021) 13235-13245. [PMID: 34708648]

[EC created 2022]

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