Thiamine Pyrophosphate, a Coenzyme of Transketolase

Racker, Efraim; Haba, G. de la; Leder, Irwin G.

doi:10.1021/ja01100a526

Cited by 238 publications

(64 citation statements)

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“…After complete resolution the addition of ThDP and a divalent cation are absolutely necessary to restore catalytic activity [57]. It has also been shown that a loss of activity can be prevented by the addition of cofactors during the puri®cation of TKs from yeasts [20,24,57,74,124,156], consistent with the pH conditions of resolution procedures being similar to the pH conditions of optimised puri®cation protocols. In contrast, partially puri®ed mammalian TKs do not require the addition of cofactors to maintain activity.…”

Section: Cofactor Requirementsmentioning

confidence: 55%

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Properties and functions of the thiamin diphosphate dependent enzyme transketolase

Schenk

Duggleby

Nixon

1998

The International Journal of Biochemistry & Cell Biology

221

164

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This review highlights recent research on the properties and functions of the enzyme transketolase, which requires thiamin diphosphate and a divalent metal ion for its activity. The transketolase-catalysed reaction is part of the pentose phosphate pathway, where transketolase appears to control the non-oxidative branch of this pathway, although the overall¯ux of labelled substrates remains controversial. Yeast transketolase is one of several thiamin diphosphate dependent enzymes whose three-dimensional structures have been determined. Together with mutational analysis these structural data have led to detailed understanding of thiamin diphosphate catalysed reactions. In the homodimer transketolase the two catalytic sites, where dihydroxyethyl groups are transferred from ketose donors to aldose acceptors, are formed at the interface between the two subunits, where the thiazole and pyrimidine rings of thiamin diphosphate are bound. Transketolase is ubiquitous and more than 30 full-length sequences are known. The encoded protein sequences contain two motifs of high homology; one common to all thiamin diphosphate-dependent enzymes and the other a unique transketolase motif. All characterised transketolases have similar kinetic and physical properties, but the mammalian enzymes are more selective in substrate utilisation than the nonmammalian representatives. Since products of the transketolase-catalysed reaction serve as precursors for a number of synthetic compounds this enzyme has been exploited for industrial applications. Putative mutant forms of transketolase, once believed to predispose to disease, have not stood up to scrutiny. However, a modi®cation of transketolase is a marker for Alzheimer's disease, and transketolase activity in erythrocytes is a measure of thiamin nutrition. The cornea contains a particularly high transketolase concentration, consistent with the proposal that pentose phosphate pathway activity has a role in the removal of light-generated radicals. #

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Section: Cofactor Requirementsmentioning

confidence: 55%

“…The necessity of divalent metal ions for activity has been shown for baker's yeast TK [57,124]. The reconstitution rate of this enzyme increases in the order Ni 2+ < Mg 2+ < Co 2+ < Mn 2+ <Ca 2+ , but the ®nal catalytic activity is independent of the nature of the divalent metal ion [57].…”

Section: Cofactor Requirementsmentioning

confidence: 99%

Properties and functions of the thiamin diphosphate dependent enzyme transketolase

Schenk

Duggleby

Nixon

1998

The International Journal of Biochemistry & Cell Biology

221

164

View full text Add to dashboard Cite

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“…TPP is a cofactor for numerous enzymatic reactions including pyruvate dehydrogenase (PDH), transketolase, α-ketogluterate dehydrogenase (KGDH) and branched-chain α-keto acid dehydrogenase (BCKDH) [9,[53][54][55]. Its involvement in these metabolic pathways and its intracellular abundance has made TPP a popular analyte for assessing thiamine status.…”

Section: Physiology Of Thiaminementioning

confidence: 99%

Vitamin B1 in critically ill patients: needs and challenges

Collie

Greaves

Jones

et al. 2017

Clinical Chemistry and Laboratory Medicine (CCLM)

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Background: Thiamine has a crucial role in energy production, and consequently thiamine deficiency (TD) has been associated with cardiac failure, neurological disorders, oxidative stress (lactic acidosis and sepsis) and refeeding syndrome (RFS). This review aims to explore analytical methodologies of thiamine compound quantification and highlight similarities, variances and limitations of current techniques and how they may be relevant to patients. Content: An electronic search of Medline, PubMed and Embase databases for original articles published in peerreviewed journals was conducted. MethodsNow was used to search for published analytical methods of thiamine compounds. Keywords for all databases included "thiamine and its phosphate esters", "thiamine methodology" and terms related to critical illness. Enquiries were also made to six external quality assurance (EQA) programme organisations for the inclusion of thiamine measurement.

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“…More specifically, the oxidation of the glycolaldehyde-thiamine pyrophosphate addition compound has been proposed (Bassham and Calvin, 1962;. This glycolaldehyde thia~ine -2-pyrophosphate addition ccmpound appears to be the intermediate canpound (Breslow, 1958) in the transketolase reaction (Racker ~ al., 1953;Horecker ~ al., 1953), and it is also involved (White and Ingraham, 1962) in the phosphoketolase reaction (Heath et al, 1958). Its proposed oxidation might involve concammitant reduction of a disulfide (such as lipoic acid) to disulfhydryl, which directly or indirectly might be reoxidized by o 2 • Therefore, we have looked for effects of 0 2 on the formation of glycolic acid and other early products of photosynthetic C02 .reduction during photosynthesis, as well as effects on the total C02 incorporation.…”

mentioning

confidence: 99%