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G5507 Sigma-Aldrich

Galactosyltransferase from bovine milk

lyophilized powder

Synonym: Lactose Synthase, UDP-galactose:D-glucose 4-β-galactosyltransferase



Related Categories 2.4.x.x Glycosyltransferases, 2.x.x.x Transferases, Application Index, Biochemicals and Reagents, Carbohydrate Hydrolysis,
Quality Level   200
form   lyophilized powder
activity   3.0-15.0 units/mg protein (in the presence of adequate α-lactalbumin, without added α-lactalbumin the activity is zero)
composition   Protein, 35-65% modified Warburg-Christian
impurities   ≤10 % protein α-lactalbumin
storage temp.   −20°C


General description

Galactosyltransferases belong to the galactosyltransferase family and are anchored to the membrane of Golgi through their N-terminal region.


Galactosyltransferase from bovine milk has been used:
•  in the generation of hyper-galactosylated variant of IgG1
• in β -1,4-galactosyltransferase assay rice root cell extracts
•  in the modification of LacNAcQ11 and LacDiNAcQ11 nanofibers

Galactosyltransferase is the catalytic component of the lactose synthetase system; it synthesizes lactose slowly in the absence of the regulatory protein α-lactalbumin. Galactosyltransferase will also transfer galactose from UDP-galactose to N-acetylglucosamine. This preparation is useful in the determination of α-lactalbumin, UDP-galactose, and N-acetylglucosamine.


25 units in glass bottle

5, 10 units in serum bottle

Biochem/physiol Actions

Galactosyltransferase catalyzes the transfer of galactosyl molecules in the synthesis of oligosaccharides.

Galactosyltransferase from bovine milk requires Mn2+ ions for its catalytic functionality. Alteration in the galactosyltransferase levels have been implicated in various diseases states.


This is probably the same enzyme as N-acetyllactosamine synthetase, EC and EC

Unit Definition

One unit will transfer 1.0 μmole of galactose from UDP-galactose to D-glucose per min at pH 8.4 at 30 °C in the presence of 0.2 mg α-lactalbumin per mL of reaction mixture. (without added α-lactalbumin the activity is zero)

Physical form

Lyophilized powder containing Tris, EDTA, and (NH4)2SO4

Safety & Documentation

Safety Information

Personal Protective Equipment 
NONH for all modes of transport
WGK Germany 
Flash Point(F) 
Not applicable
Flash Point(C) 
Not applicable
Protocols & Articles



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