ENZYME

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A new class EC 7, Translocases, has been added to the EC list. It will be part of ENZYME from release 2018_10. Read more about EC 7 here.

ENZYME entry: EC 2.4.1.184

Accepted Name

Galactolipid galactosyltransferase.

Alternative Name(s)

DGDG synthase.

Digalactosyldiacylglycerol synthase.

Galactolipid-galactolipid galactosyltransferase.

GGGT.

Interlipid galactosyltransferase.

Reaction catalysed

2 a 1,2-diacyl-3-O-(beta-D-galactosyl)-sn-glycerol <=> a 1,2-diacyl-3-O-(beta-D-galactosyl-(1->6)-beta-D-galactosyl)-sn-glycerol + a 1,2-diacyl-sn-glycerol

Comment(s)

The enzyme converts monogalactosyldiacylglycerol to digalactosyldiacylglycerol, trigalactosyldiacylglycerol and tetragalactosyldiacylglycerol.
All residues are connected by beta linkages.
The activity is localized to chloroplast envelope membranes, but it does not contribute to net galactolipid synthesis in plants, which is performed by EC 2.4.1.46 and EC 2.4.1.241.
Note that the beta,beta-digalactosyldiacylglycerol formed by this enzyme is different from the more common alpha,beta- digalactosyldiacylglycerol formed by EC 2.4.1.241.
The enzyme provides an important mechanism for the stabilization of the chloroplast membranes during freezing and drought stress.

Cross-references

BRENDA

2.4.1.184

EC2PDB

2.4.1.184

ExplorEnz

2.4.1.184

PRIAM enzyme-specific profiles

2.4.1.184

KEGG Ligand Database for Enzyme Nomenclature

2.4.1.184

IUBMB Enzyme Nomenclature