Biochemistry

+ С -QL О О II II II С-СН^СНз-О-Р-О-Р- он он он Thiamine pyrophosphate Thiamine pyrophosphate (cocarboxylase) is a coenzyme of keto acid decarboxylases and is part of several enzyme systems that catalyze the decarboxylation of many a-keto acids. Thus, TPP is one of the со -enzymes of pyruvate dehydrogenase, which catalyzes an oxidative phosphorylation of pyruvic acid to acetyl-CoA and a-keto-glutarate dehydrogenase, which decarboxylates a- ketoglutaric acid to form an active form of succinic acid - succinyl-CoA. TPP is also part of the transketolase, which provides the pentose phosphate cycle. This leads to biosynthesis processes disorder, in particular, nucleotides, nucleic acids, proteins, higher fatty acids, cholesterol and other compounds. Phosphorylated thiamine derivatives in addition to coenzyme functions, are involved in other reactions. Thiamine diphosphate and thiamine triphosphate can play the role of macroergs, and thiol disulfide derivatives of thiamine are able to affect on redox reactions. Vitamin В i is involved in protein metabolism, providing the process of transamination of ammo acids; regulates endogenous fat synthesis and promotes the accumulation of unsaturated fatty acids in the body. Vitamin В i improves the transmission of nerve impulses, delaying the breakdown of acetylcholine by cholinesterase, and increases the body's resistance to infectious diseases. Thiamine deficiency. A deficiency of vitamin В i leads to В i vitamin deficiency (beriberi disease) in the body, which is manifested by multiple inflammation of the peripheral nerves, muscle soreness, decreased skin sensitivity, ambulation disorder due to the accumulation of keto acids, especially pyruvic acid in the brain tissues. Such patients have difficulties with walking. They have rapid fatigability, increased irritability, and sleep disturbance. Later, they have disorders of the gastrointestinal tract: a decreased appetite, diarrhea alternating with constipation, and decreased body weight. Functions of the respiratory, cardiovascular systems, liver, etc. are impaired. At present, beriberi is very rare, but thiamine deficiency has become one of the most common manifestations of hypovitaminosis among the population in all economically developed countries. This can be explained by an increase in the consumption of refined products (bakery, pasta from premium flour, confectionery, 247