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Literature summary for 2.7.7.69 extracted from

  • Dowdle, J.; Ishikawa, T.; Gatzek, S.; Rolinski, S.; Smirnoff, N.
    Two genes in Arabidopsis thaliana encoding GDP-L-galactose phosphorylase are required for ascorbate biosynthesis and seedling viability (2007), Plant J., 52, 673-689.
    View publication on PubMed
Search for more literature for 2.7.7.69

Protein Variants

Protein Variants Comment Organism
additional information construction of isoforms Vtc2/Vtc5 double mutants. Double mutants show growth arrest immediately upon germination and the cotyledons subsequently bleach. Normal growth is restored by supplementation with ascorbate or L-galactose Arabidopsis thaliana
additional information construction of isoforms Vtc2/Vtc5 double mutants. Double mutants show growth arrest immediately upon germination and the cotyledons subsequently bleach. Normal growth is restored by supplementation with ascorbate or L-galactose. vtc2-1 leaves contain more mannose 6-phosphate than wild-type Arabidopsis thaliana

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
0.13
-
 phosphate pH 7.5, 20°C Arabidopsis thaliana
0.25
-
 GDP-alpha-L-galactose pH 7.5, 20°C Arabidopsis thaliana
0.251
-
 phosphate pH 7.5, 20°C Arabidopsis thaliana
0.667
-
 GDP-alpha-L-galactose pH 7.5, 20°C Arabidopsis thaliana

Organism

Organism UniProt Comment Textmining
Arabidopsis thaliana Q8RWE8 isoform Vtc2
-
Arabidopsis thaliana Q9FLP9 isoform Vtc5
-

Source Tissue

Source Tissue Comment Organism Textmining
leaf VTC2 expression and GDP-L-galactose phosphorylase activity rapidly increase on transfer to high light, but the activity of other enzymes in the GDP-mannose pathway is little affected. Leaves accumulate more ascorbate after acclimatization to high light intensity Arabidopsis thaliana
-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
ADP-alpha-D-glucose + phosphate 0.1% of the activity with GDP-L-galactose Arabidopsis thaliana alpha-D-glucose 1-phosphate + ADP
-
 r
ADP-alpha-D-glucose + phosphate 0.4% of the activity with GDP-L-galactose Arabidopsis thaliana alpha-D-glucose 1-phosphate + ADP
-
 r
alpha-L-galactose 1-phosphate + GDP
-
 Arabidopsis thaliana GDP-alpha-L-galactose + phosphate
-
 r
GDP-alpha-D-mannose + phosphate 0.1% of the activity with GDP-L-galactose Arabidopsis thaliana alpha-D-mannose 1-phosphate + GDP
-
 r
GDP-alpha-D-mannose + phosphate 3.7% of the activity with GDP-L-galactose Arabidopsis thaliana alpha-D-mannose 1-phosphate + GDP
-
 r
GDP-beta-L-galactose + phosphate
-
 Arabidopsis thaliana GDP + beta-L-galactose 1-phosphate
-
 r
UDP-alpha-D-galactose + phosphate 0.1% of the activity with GDP-L-galactose Arabidopsis thaliana alpha-D-galactose 1-phosphate + UDP
-
 r
UDP-alpha-D-galactose + phosphate 0.2% of the activity with GDP-L-galactose Arabidopsis thaliana alpha-D-galactose 1-phosphate + UDP
-
 r
UDP-alpha-D-glucose + phosphate 0.3% of the activity with GDP-L-galactose Arabidopsis thaliana alpha-D-glucose 1-phosphate + UDP
-
 r
UDP-alpha-D-glucose + phosphate 2.1% of the activity with GDP-L-galactose Arabidopsis thaliana alpha-D-glucose 1-phosphate + UDP
-
 r

Turnover Number [1/s]

Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
2.04
-
 GDP-alpha-L-galactose pH 7.5, 20°C Arabidopsis thaliana
2.68
-
 GDP-alpha-L-galactose pH 7.5, 20°C Arabidopsis thaliana