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Thiamine pyrophosphate is a cofactor that is present in all living systems, in which it catalyzes several biochemical reactions. Thiamine pyrophosphate is synthesized in the cytosol and is required in the cytosol for the activity of transketolase and in the mitochondria for the activity of pyruvate-, oxoglutarate- and branched chain keto acid ...
Thiamine pyrophosphate (TPP), also called thiamine diphosphate (ThDP), participates as a coenzyme in metabolic reactions, including those in which polarity inversion takes place. [23] Its synthesis is catalyzed by the enzyme thiamine diphosphokinase according to the reaction thiamine + ATP → TPP + AMP (EC 2.7.6.2).
It serves as a riboswitch [1] [2] that binds thiamine pyrophosphate (TPP) directly and modulates gene expression through a variety of mechanisms in archaea, bacteria and eukaryotes. [3] [4] [5] TPP is the active form of thiamine (vitamin B 1), an essential coenzyme synthesised by coupling of pyrimidine and thiazole moieties in bacteria.
The conversion requires the coenzyme thiamine pyrophosphate. Pyruvate dehydrogenase is usually encountered as a component, referred to as E1, of the pyruvate dehydrogenase complex (PDC). PDC consists of other enzymes, referred to as E2 and E3. Collectively E1-E3 transform pyruvate, NAD +, coenzyme A into acetyl-CoA, CO 2, and NADH.
Thiamine in the human body has a half-life of 17 days and is quickly exhausted, particularly when metabolic demands exceed intake. A derivative of thiamine, thiamine pyrophosphate (TPP), is a cofactor involved in the citric acid cycle, as well as connecting the breakdown of sugars with the citric acid cycle.
Within the field of biochemistry, 4-amino-5-hydroxymethyl-2-methylpyrimidine (HMP) also known as toxopyrimidine together with its mono phosphate (HMP-P) and pyrophosphate (HMP-PP) esters are biogenetic precursors to the important biochemical cofactor thiamine pyrophosphate (TPP), a derivative of thiamine (vitamin B 1).
Thiamine monophosphate, also known as ThMP and TMP, is a phosphate ester of thiamine. [1] It is an intermediate from the hydrolysis of thiamine diphosphate to free thiamine by alkaline phosphatase. [2] [3] [4] The conversion of ThMP to thiamine cannot be facilitated by acid hydrolysis. [5]
Apart from the baseline enzyme activity (which may be normal even in deficiency states), acceleration of enzyme activity after the addition of thiamine pyrophosphate may be diagnostic of thiamine deficiency (0-15% normal, 15-25% deficiency, >25% severe deficiency). [12]