transketolase activity

Definition

Target type: molecularfunction

Catalysis of the reversible transfer of a 2-carbon ketol group (CH2OH-CO-) from a ketose phosphate donor to an aldose phosphate acceptor. [GOC:fmc, RHEA:10508]

Transketolase activity refers to the enzymatic transfer of a two-carbon ketol unit (specifically, a glycolaldehyde moiety) from a ketose donor to an aldose acceptor. This reaction is a crucial step in the non-oxidative branch of the pentose phosphate pathway, which plays a vital role in various metabolic processes. The enzyme transketolase, which catalyzes this reaction, is a thiamine diphosphate (TPP)-dependent enzyme. The mechanism involves the initial binding of the ketose donor to the TPP cofactor, forming a carbanion intermediate. This intermediate then reacts with the aldose acceptor, transferring the two-carbon ketol unit and regenerating the free TPP cofactor. This transfer reaction is essential for the interconversion of various sugars, particularly the production of pentose sugars like ribose-5-phosphate, which is a key component of nucleotides and nucleic acids. Transketolase activity is also involved in the synthesis of erythrose-4-phosphate, a precursor for aromatic amino acids. Therefore, transketolase activity plays a crucial role in carbohydrate metabolism, nucleotide biosynthesis, and the synthesis of aromatic amino acids.'
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Proteins (1)

Compounds (2)