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Ketolase

Orange carotenoid protein Conserved hypothetical protein (sir 1964) ft- OCP N terminal domain OCP C-terminal domain Hypothetical protein Hypothetical protein D- Beta carotene ketolase homolog Hydrolase... [Pg.6]

The answer is A. This patient exhibits several signs of acute arsenic exposure, including the cholera-like gastrointestinal symptoms and probable dehydration. He may currently be in hypovolemic shock and beginning chelation therapy is the only recourse. Arsenic is a metabolic toxin because it inhibits enzymes that require lipoic acid as a coenzyme the PDH complex, the a-ketoglutarate dehydrogenase complex, and trans-ketolase of the pentose phosphate pathway. [Pg.102]

The transketolase-catalyzed conversion of xylulose-5-phosphate and ribose-5-phosphate to glyceraldehyde-3-phosphate and sedoheptulose-7-phosphate. Although the aldolase and ketolase reactions superficially resemble each other, they proceed by very different mechanisms. This is because in the aldolase reaction the carbon adjacent to a carbonyl... [Pg.274]

Stage 3 - Linkage of the pentose phosphate pathway to glycolysis via trans-ketolase and transaldolase... [Pg.300]

Genetic defects of the tissue thiamin transport protein and thiamin pyrophosphokinase cause megaloblastic anemia, presumahly as a result of impaired synthesis of pentoses for DNA synthesis from low activity of trans-ketolase (Section 6.3.2). In many cases, this megaloblastic anemia is thiamin-responsive, suggesting that the defect must be because of low af nity of either the transport protein or thiarnin pyrophosphokinase for its substrate (Neufeld et al., 2001). [Pg.152]

Lange, B.M., WUdung, M.R., McCaskill, D., and Croteau, R. (1998). A family of trans-ketolases that directs isoprenoid biosynthesis via a mevalonate-independent pathway. Proc Natl Acad Sci USA 95 2100-2104. [Pg.292]

Reference intervals for thiamine and its esters depend upon whether (1) erythrocytes, whole blood, or plasma are used as a sample (2) cellular concentrations are expressed per liter of packed red cells or grams of Hb and (3) mass or SI units are used. Some guidance intervals are, for erythrocyte trans-ketolase activity 0.75 to 1.30U/g Hb (48.4 to 83.9kU/mol Hb) and for percent TPP effect (activation), 0 to 15% is normal, 16% to 25% marginally deficient and >25% severely... [Pg.1094]

Lyases Catalyze the nonhydrolytic removal of groups Decarboxylases, aldolases, ketolases, hydratases, dehydratases... [Pg.105]

All biochemical reactions with participation of thiamine start with C-C-bond cleavage of 2-oxo carbonyl-compound and proceed with formation of an activated aldehyde , TPP catalyzes decarboxylation of a-keto acids, oxidative decarboxylations together with lipoic acid, and trans-ketolase reactions. [Pg.21]

Fig. 11.3 Simplified diagram of isoprenoid metabolic pathway relative to the conversions among carotenoids that have been genetically manipulated. Enzymes catalysing some key reactions are indicated by the following abbreviations IPI, isopentenyl pyrophosphate isomerase PSY, phytoene synthase PDS, phytoene desaturase (crti, gene from Erwinia uredovora) ZDS, -carotene desaturase LCYB, lycopene / -cyclase CRTR-b, /3-carotene 3,3 -hydroxylase CCS, capsanthin-capsombin synthase CRTO, /3-carotene ketolase. Fig. 11.3 Simplified diagram of isoprenoid metabolic pathway relative to the conversions among carotenoids that have been genetically manipulated. Enzymes catalysing some key reactions are indicated by the following abbreviations IPI, isopentenyl pyrophosphate isomerase PSY, phytoene synthase PDS, phytoene desaturase (crti, gene from Erwinia uredovora) ZDS, -carotene desaturase LCYB, lycopene / -cyclase CRTR-b, /3-carotene 3,3 -hydroxylase CCS, capsanthin-capsombin synthase CRTO, /3-carotene ketolase.
Breitenbach J, Misawa N, Kajiwara S and Sandmann G (1996) Expression in Escherichia coli and properties of the carotene ketolase from Haematococcus pluvialis. FEMS Microbiol Lett 140 241-246... [Pg.65]

Bacterial p-carotene hydroxylases, CrtZ, were characterized with respect to substrate specificity and reaction mechanism after expression in E. coli. The reactions depend on oxygen and are stimulated by 2-oxoglutarate, ascorbate, and Fe L which is typical for a dioxygenase reaction. Similar mechanistic properties were also found for bacterial ketolases encoded by crtW. These enzymes catalyze the introduction of... [Pg.360]

Kim JE, Cheng KM, Craft NE, Hamberger B, Douglas CJ (2010) Over-expression of Arabidopsis thaliana carotenoid hydroxylases individually and in combination with a P-carotene ketolase provides insight into in vivo functions. Phytochemistry 71 168-178... [Pg.442]

See other pages where Ketolase is mentioned: [Pg.587]    [Pg.165]    [Pg.369]    [Pg.380]    [Pg.4]    [Pg.686]    [Pg.377]    [Pg.972]    [Pg.274]    [Pg.334]    [Pg.94]    [Pg.524]    [Pg.479]    [Pg.241]    [Pg.74]    [Pg.152]    [Pg.146]    [Pg.232]    [Pg.308]    [Pg.631]    [Pg.962]    [Pg.294]    [Pg.603]    [Pg.59]    [Pg.25]    [Pg.483]    [Pg.507]    [Pg.38]    [Pg.201]    [Pg.201]    [Pg.649]    [Pg.303]    [Pg.43]    [Pg.5727]   
See also in sourсe #XX -- [ Pg.603 ]



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Aldolases and Ketolases

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