Explain the Coenzyme in enzyme catalyzed reactions?

Thiamin functions as the coenzyme thiamin pyrophosphate (TPP) in the inetabolism of carbohydrates and branched- chain amino acids. Specifically the Mg² +coordinated TPP participates in the formation of α-ketols (e.g. among hexose and pentose phosphates as described in the reaction given at point iv below) as catalyzed, by transketolase and in the oxidation of a-keto acids (e.g. pyruvate, α-ketoglutarate, and branchedchain α- keto acids) by dehydrogenese complexes (refer to reaction ii and iii). Hence, when there is insufficient thiamin, the overall decrease in carbohydrate metabolism and its interconnection with amino acid metabolism (via a-keto acids) has severe consequences, such as a decrease in the formation of acetylcholine for neural function.