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Literature summary for 2.4.1.38 extracted from

  • Ramakrishnan, B.; Boeggeman, E.; Qasba, P.K.
    Mutation of arginine 228 to lysine enhances the glucosyltransferase activity of bovine beta-1,4-galactosyltransferase I (2005), Biochemistry, 44, 3202-3210.
    View publication on PubMed

Crystallization (Commentary)

Crystallization (Comment) Organism
catalytic domain of R228K-Gal-T1 and mouse recombinant alpha-lactalbumin are cocrystallized in the presence of UDP-galactose and MnCl2. Crystals are grown at room temperature by the hanging drop method. Crystal structure of R228K-Gal-T1 complexed with alpha-lactalbumin, UDP-galactose, and Mn2+, determined at 1.9 Å resolution shows that the Asp318 side chain exhibits a minor alternate conformation, compared to that in the wild type Bos taurus

Protein Variants

Protein Variants Comment Organism
R228K mutant enzyme shows 16% of the wild-type galactosyltransferase activity, mutation results in a 15fold higher glucosyltransferase activity, which is further enhanced by alpha-lactalbumin to nearly 25% of the galactosyltransferase activity of the wild type. The main effect of the mutation is on the kcat of glucosyltransferase, which increases 3-4fold, both in the absence and in the presence of alpha-lactalbumin simultaneously, the kcat for the galactosyltransferase reaction is reduced 30fold Bos taurus

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
0.0007
-
N-acetylglucosamine cosubstrate: UDP-galactose, in presence of alpha-lactalbumin, mutant enzyme R228K Bos taurus
0.0013
-
N-acetylglucosamine cosubstrate: UDP-glucose, in presence of alpha-lactalbumin, mutant enzyme R228K Bos taurus
0.0025
-
N-acetylglucosamine cosubstrate: UDP-glucose, in presence of alpha-lactalbumin, wild-type enzyme Bos taurus
0.009
-
N-acetylglucosamine cosubstrate: UDP-glucose, without alpha-lactalbumin, mutant enzyme R228K Bos taurus
0.0105
-
UDP-galactose cosubstrate: N-acetylglucosamine, in presence of alpha-lactalbumin, mutant enzyme R228K Bos taurus
0.011
-
N-acetylglucosamine cosubstrate: UDP-galactose, without alpha-lactalbumin, mutant enzyme R228K Bos taurus
0.011
-
N-acetylglucosamine cosubstrate: UDP-galactose, without alpha-lactalbumin, wild-type enzyme Bos taurus
0.031
-
UDP-glucose cosubstrate: N-acetylglucosamine, in presence of alpha-lactalbumin, wild-type enzyme Bos taurus
0.044
-
UDP-glucose cosubstrate: N-acetylglucosamine, in presence of alpha-lactalbumin, mutant enzyme R228K Bos taurus
0.074
-
N-acetylglucosamine cosubstrate: UDP-glucose, without alpha-lactalbumin, wild-type enzyme Bos taurus
0.087
-
UDP-galactose cosubstrate: N-acetylglucosamine, without alpha-lactalbumin, mutant enzyme R228K Bos taurus
0.091
-
UDP-glucose cosubstrate: N-acetylglucosamine, without alpha-lactalbumin, mutant enzyme R228K Bos taurus
0.093
-
UDP-galactose cosubstrate: N-acetylglucosamine, without alpha-lactalbumin, wild-type enzyme Bos taurus
0.148
-
UDP-glucose cosubstrate: N-acetylglucosamine, without alpha-lactalbumin, wild-type enzyme Bos taurus

Organism

Organism UniProt Comment Textmining
Bos taurus
-
-
-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
UDP-galactose + N-acetylglucosamine
-
Bos taurus UDP + beta-D-galactosyl-1,4-N-acetyl-beta-D-glucosamine
-
?
UDP-glucose + N-acetylglucosamine reaction with 0.3% efficiency. R228K mutation results in a 15-fold higher glucosyltransferase activity, which is further enhanced by alpha-lactalbumin to nearly 25% of the galactosyltransferase activity of the wild type Bos taurus UDP + beta-D-glucosyl-1,4-N-acetyl-beta-D-glucosamine
-
?

Synonyms

Synonyms Comment Organism
(alpha4Gal-T1)
-
Bos taurus
alpha-1,4-galactosyltransferase I
-
Bos taurus

Turnover Number [1/s]

Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
0.06
-
UDP-glucose cosubstrate: N-acetylglucosamine, without alpha-lactalbumin, wild-type enzyme Bos taurus
0.06
-
N-acetylglucosamine cosubstrate: UDP-glucose, without alpha-lactalbumin, wild-type enzyme Bos taurus
0.17
-
UDP-glucose cosubstrate: N-acetylglucosamine, without alpha-lactalbumin, mutant enzyme R228K Bos taurus
0.17
-
N-acetylglucosamine cosubstrate: UDP-glucose, without alpha-lactalbumin, mutant enzyme R228K Bos taurus
0.25
-
UDP-glucose cosubstrate: N-acetylglucosamine, in presence of alpha-lactalbumin, wild-type enzyme Bos taurus
0.25
-
N-acetylglucosamine cosubstrate: UDP-glucose, in presence of alpha-lactalbumin, wild-type enzyme Bos taurus
0.33
-
UDP-galactose cosubstrate: N-acetylglucosamine, in presence of alpha-lactalbumin, mutant enzyme R228K Bos taurus
0.33
-
N-acetylglucosamine cosubstrate: UDP-galactose, in presence of alpha-lactalbumin, mutant enzyme R228K Bos taurus
0.52
-
UDP-galactose cosubstrate: N-acetylglucosamine, without alpha-lactalbumin, mutant enzyme R228K Bos taurus
0.52
-
N-acetylglucosamine cosubstrate: UDP-galactose, without alpha-lactalbumin, mutant enzyme R228K Bos taurus
0.96
-
UDP-glucose cosubstrate: N-acetylglucosamine, in presence of alpha-lactalbumin, mutant enzyme R228K Bos taurus
0.96
-
N-acetylglucosamine cosubstrate: UDP-glucose, in presence of alpha-lactalbumin, mutant enzyme R228K Bos taurus
14
-
UDP-galactose cosubstrate: N-acetylglucosamine, without alpha-lactalbumin, wild-type enzyme Bos taurus
14
-
N-acetylglucosamine cosubstrate: UDP-galactose, without alpha-lactalbumin, wild-type enzyme Bos taurus