Final answer:
Transketolase catalyzes the transketolation reaction where a two-carbon moiety is transferred. The enzyme requires Thiamine pyrophosphate (TPP) and is crucial in metabolic pathways such as the pentose phosphate pathway.
Step-by-step explanation:
The reaction catalyzed by transketolase is known as a transketolation reaction. This is a biochemical reaction where a two-carbon moiety, active glycelaldehyde, is transferred. Transketolase, the enzyme facilitating this process, requires Thiamine pyrophosphate (TPP) as a coenzyme. A deficiency in thiamine, such as in pernicious anemia, leads to a decrease in transketolase activity in the blood. The importance of transketolase lies within the pentose phosphate pathway where it plays a crucial role in the generation of NADPH and ribose-5-phosphate, both essential for the biosynthesis of nucleotides and lipid metabolism.
Transketolase is one example of an enzyme that catalyzes reactions involving a five-member transition state. Enzyme-catalyzed reactions like those involving transketolase are often stereospecific, influencing the three-dimensional arrangement of the atoms within a molecule.