Transaldolase

Transaldolase is an enzyme (EC 2.2.1.2) of the non-oxidative phase of the pentose phosphate pathway. In humans, transaldolase is encoded by the TALDO1 gene.^[3][4]

The following chemical reaction is catalyzed by transaldolase:

sedoheptulose 7-phosphate + glyceraldehyde 3-phosphate ${\displaystyle \rightleftharpoons }$ erythrose 4-phosphate + fructose 6-phosphate

Clinical significance

The pentose phosphate pathway has two metabolic functions: (1) generation of nicotinamide adenine dinucleotide phosphate (reduced NADPH), for reductive biosynthesis, and (2) formation of ribose, which is an essential component of ATP, DNA, and RNA. Transaldolase links the pentose phosphate pathway to glycolysis. In patients with deficiency of transaldolase, there's an accumulation of erythritol (from erythrose 4-phosphate), D-arabitol, and ribitol.^[5][6]

The deletion in 3 base pairs in the TALDO1 gene results in the absence of serine at position 171 of the transaldolase protein, which is part of a highly conserved region, suggesting that the mutation causes the transaldolase deficiency that is found in

Transaldolase is a single domain composed of 337 amino acids. The core structure is an

The active site, located in the center of the barrel, contains three key residues: lysine-142, glutamate-106, and aspartate-27. The lysine holds the sugar in place while the glutamate and aspartate act as proton donors and acceptors.[1]

Mechanism of catalysis

The residue of lysine-142 in the active site of transaldolase forms a

See also

• Transaldolase deficiency

References