ThiaminpyrophosphatAktivität

Thiamin pyrophosphate (TPP) is the active coenzyme form of vitamin B1. It is produced in cells by phosphorylation of thiamine through the action of the enzyme thiamine pyrophosphokinase, resulting in the diphosphate ester thiamin pyrophosphate. TPP consists of a thiazolium ring connected to a diphosphate moiety and requires magnesium ions for stability and activity. As a water-soluble molecule, vitamin B1 is obtained from the diet and stored in limited amounts in the body.

In metabolism, TPP acts as a critical cofactor for several enzymes involved in carbohydrate metabolism and energy production. It participates in the catalytic decarboxylation of alpha-keto acids and in the transfer of two-carbon units. The best-known reactions occur in the pyruvate dehydrogenase complex, which converts pyruvate to acetyl-CoA; the alpha-ketoglutarate dehydrogenase complex of the citric acid cycle; and the branched-chain alpha-ketoacid dehydrogenase complex. TPP is also a cofactor for transketolase in the pentose phosphate pathway, enabling transfer of two-carbon units between sugar phosphates.

Deficiency of thiamine or impaired activation reduces TPP availability and disrupts energy production, leading to neurological and cardiovascular symptoms. Severe deficiency can cause beriberi and Wernicke–Korsakoff syndrome, particularly in individuals with malnutrition, chronic alcohol use, or malabsorption. Dietary sources include pork, whole grains, legumes, and fortified cereals. Stores are limited, so adequate intake or supplementation is important for maintaining TPP-dependent enzymatic activities.