Phosphotransferase.

Mannose-1-phosphate guanylyltransferase 1; Catalyzes a reaction of the Smirnoff-Wheeler pathway, the major route to ascorbate biosynthesis in plants. Plays an essential role in plant growth and development and cell-wall architecture. Provides GDP-mannose, used for cell wall carbohydrate biosynthesis, protein N-glycosylation, as well as for the biosynthesis of the antioxidant ascorbate.

Phosphotransferase.

L-galactono-1,4-lactone dehydrogenase, mitochondrial; Involved in the biosynthesis of ascorbic acid. Required for the accumulation of respiratory complex I. Uses L-galactono-1,4-lactone and L-gulono-1,4-lactone as substrates, but not D-galactono-1,4- lactone, D-gulono-1,4-lactone, L-mannono-1,4-lactone or D-galactonic acid. Also active with phenazine methosulfate and 1,4-benzoquinone as electron acceptors.

Phosphotransferase.

GDP-mannose 3,5-epimerase; Catalyzes a reversible epimerization of GDP-D-mannose that precedes the committed step in the biosynthesis of vitamin C (L- ascorbate), resulting in the hydrolysis of the highly energetic glycosyl-pyrophosphoryl linkage. Able to catalyze 2 distinct epimerization reactions and can release both GDP-L-galactose and GDP-L- gulose from GDP-mannose.

Phosphotransferase.

L-galactose dehydrogenase; Catalyzes the oxidation of L-galactose to L-galactono-1,4- lactone in the presence of NAD(+). Uses NAD(+) as a hydrogen acceptor much more efficiently than NADP(+); Belongs to the aldo/keto reductase family.

Phosphotransferase.

Glucose-6-phosphate isomerase, cytosolic; Belongs to the GPI family.

Phosphotransferase.

Mannose-6-phosphate isomerase 1; Involved in the synthesis of the GDP-mannose and dolichol- phosphate-mannose required for a number of critical mannosyl transfer reactions. Involved in the ascorbic acid (AsA) biosynthesis. Required during the endosperm development.

Phosphotransferase.

Mannose-6-phosphate isomerase 2; Involved in the synthesis of the GDP-mannose and dolichol- phosphate-mannose required for a number of critical mannosyl transfer reactions.

Phosphotransferase.

Inositol-phosphate phosphatase; Phosphatase acting on L-galactose 1-phosphate (L-Gal 1-P), D- myoinositol 3-phosphate (D-Ins 3-P) and D-myoinositol 1-phosphate (D- Ins 1-P). Can also use beta-glycerophosphate (glycerol 2-P) and, to a lesser extent, D-galactose 1-phosphate (D-Gal 1-P), alpha-D-glucose 1- phosphate (a-D-Glc 1-P), D-manitol 1-phosphate and adenosine 2'- monophosphate as substrates. No activity with D-fructose 1-phosphate (D-Fru 1-P), fructose 1,6-bisphosphate (Fru 1,6-bisP), D-glucose 6- phosphate (D-Glc 6-P), D-alpha-glycerophosphate (glycerol 3-P), D- sorbitol 6-phospha [...]

Phosphotransferase.

GDP-L-galactose phosphorylase 2; Catalyzes a reaction of the Smirnoff-Wheeler pathway, the major route to ascorbate biosynthesis in plants. Acts as a phosphorylase rather than as a transferase. Uses preferentially GDP-L- galactose and GDP-D-glucose as substrates. Lower activity with GDP-L- fucose, very low activity with GDP-D-mannose, and no activity with UDP- D-glucose, UDP-D-galactose or ADP-D-glucose. Highly specific for inorganic phosphate as the guanylyl acceptor.

Hexokinase-4; Fructose and glucose phosphorylating enzyme (By similarity). May be involved in the phosphorylation of glucose during the export from mitochondrion to cytosol (By similarity).

Mannose-1-phosphate guanylyltransferase 1; Catalyzes a reaction of the Smirnoff-Wheeler pathway, the major route to ascorbate biosynthesis in plants. Plays an essential role in plant growth and development and cell-wall architecture. Provides GDP-mannose, used for cell wall carbohydrate biosynthesis, protein N-glycosylation, as well as for the biosynthesis of the antioxidant ascorbate.

Hexokinase-4; Fructose and glucose phosphorylating enzyme (By similarity). May be involved in the phosphorylation of glucose during the export from mitochondrion to cytosol (By similarity).

L-galactono-1,4-lactone dehydrogenase, mitochondrial; Involved in the biosynthesis of ascorbic acid. Required for the accumulation of respiratory complex I. Uses L-galactono-1,4-lactone and L-gulono-1,4-lactone as substrates, but not D-galactono-1,4- lactone, D-gulono-1,4-lactone, L-mannono-1,4-lactone or D-galactonic acid. Also active with phenazine methosulfate and 1,4-benzoquinone as electron acceptors.

Hexokinase-4; Fructose and glucose phosphorylating enzyme (By similarity). May be involved in the phosphorylation of glucose during the export from mitochondrion to cytosol (By similarity).

GDP-mannose 3,5-epimerase; Catalyzes a reversible epimerization of GDP-D-mannose that precedes the committed step in the biosynthesis of vitamin C (L- ascorbate), resulting in the hydrolysis of the highly energetic glycosyl-pyrophosphoryl linkage. Able to catalyze 2 distinct epimerization reactions and can release both GDP-L-galactose and GDP-L- gulose from GDP-mannose.

Hexokinase-4; Fructose and glucose phosphorylating enzyme (By similarity). May be involved in the phosphorylation of glucose during the export from mitochondrion to cytosol (By similarity).

Hexokinase-3; Fructose and glucose phosphorylating enzyme (By similarity). May be involved in the phosphorylation of glucose during the export from mitochondrion to cytosol (By similarity).

Hexokinase-4; Fructose and glucose phosphorylating enzyme (By similarity). May be involved in the phosphorylation of glucose during the export from mitochondrion to cytosol (By similarity).

Probable hexokinase-like 2 protein; Fructose and glucose phosphorylating enzyme.

Hexokinase-4; Fructose and glucose phosphorylating enzyme (By similarity). May be involved in the phosphorylation of glucose during the export from mitochondrion to cytosol (By similarity).

Hexokinase-1; Fructose and glucose phosphorylating enzyme. May be involved in the phosphorylation of glucose during the export from mitochondrion to cytosol. Acts as sugar sensor which may regulate sugar-dependent gene repression or activation. Mediates the effects of sugar on plant growth and development independently of its catalytic activity or the sugar metabolism. May regulate the execution of program cell death in plant cells. Promotes roots and leaves growth. Belongs to the hexokinase family.

Hexokinase-4; Fructose and glucose phosphorylating enzyme (By similarity). May be involved in the phosphorylation of glucose during the export from mitochondrion to cytosol (By similarity).

Hexokinase-2; Fructose and glucose phosphorylating enzyme. May be involved in the phosphorylation of glucose during the export from mitochondrion to cytosol. Acts as sugar sensor which may regulate sugar-dependent gene repression or activation. Mediates the effects of sugar on plant growth and development independently of its catalytic activity or the sugar metabolism. May regulate the execution of program cell death in plant cells ; Belongs to the hexokinase family.

Hexokinase-4; Fructose and glucose phosphorylating enzyme (By similarity). May be involved in the phosphorylation of glucose during the export from mitochondrion to cytosol (By similarity).

Hexokinase-like 1 protein; Fructose and glucose phosphorylating enzyme. Belongs to the hexokinase family.

Hexokinase-4; Fructose and glucose phosphorylating enzyme (By similarity). May be involved in the phosphorylation of glucose during the export from mitochondrion to cytosol (By similarity).

L-galactose dehydrogenase; Catalyzes the oxidation of L-galactose to L-galactono-1,4- lactone in the presence of NAD(+). Uses NAD(+) as a hydrogen acceptor much more efficiently than NADP(+); Belongs to the aldo/keto reductase family.

Hexokinase-4; Fructose and glucose phosphorylating enzyme (By similarity). May be involved in the phosphorylation of glucose during the export from mitochondrion to cytosol (By similarity).

Glucose-6-phosphate isomerase, cytosolic; Belongs to the GPI family.

Hexokinase-4; Fructose and glucose phosphorylating enzyme (By similarity). May be involved in the phosphorylation of glucose during the export from mitochondrion to cytosol (By similarity).

Mannose-6-phosphate isomerase 1; Involved in the synthesis of the GDP-mannose and dolichol- phosphate-mannose required for a number of critical mannosyl transfer reactions. Involved in the ascorbic acid (AsA) biosynthesis. Required during the endosperm development.