D-tagatose

Tafel equation Tafel kinetics Tafel slope Taffy process Taft s SV function Tagamet [51481-61-9] d-Tagatose... 

Four DHAP converting aldolases are known, these can synthesize different diastereomers with complementary configurations D-fructose (FruA EC 4.1.2.13) and D-tagatose 1,6-bisphos-phate (TagA, F.C 4.1.2.-), L-fuculose (FucA EC 4.1.2.17) and L-rhamnulose 1-phosphate aldolase (RhuA EC 4.1.2.19)3. The synthetic application of the first (class 1 or 2) and the latter two types (class 2) has been examined. 

Figure 10.15 Enzymatic one-pot synthesis of D-tagatose 1,6-bisphosphate based on the stereoselective TagA m coli.

The taste properties of various other ketoses, including 2-pentuloses, 2-hexuloses, and 2-octuloses, have also been studied (see Table XV) to determine the significance of the 2-hydroxyl-2-hydroxymethyl arrangement of 2-ketopyranoses. Some of these, for example, a-D-tagatose (25), -d-g/uco-2-heptulose (26), a-D-mnMno-2-heptulose (27), a-D-fa/o-2-heptulose (28), a-D-a/tro-2-heptulose (29), and D-g/ycero-a-D-g/ co-2-octulose (30),... 

An interesting contrast has been observed between the respective actions of acid and alkali on 3,4-anhydro-l,2-isopropylidene-D-tagatose (XXIVo). The anhydro ring of this compound shows considerable resistance to both mineral acids and alkali. Cleavage by sodium meth-... 

This enzyme [EC 2.7.1.11], also known as phosphohexo-kinase and phosphofructokinase 1, catalyzes the reaction of ATP with D-fructose 6-phosphate to produce ADP and D-fructose 1,6-bisphosphate. Both D-tagatose 6-phosphate and sedoheptulose 7-phosphate can act as the sugar substrate. UTP, CTP, GTP, and ITP all can act as the nucleotide substrate. This enzyme is distinct from that of 6-phosphofructo-2-kinase. See also ATP GTP Depletion... 

Lactose 37 48 D-galactose (9) lactulose D-lyxose (10) resinous D-tagatose (11) 3... 

D-fructose 1,6-bisphosphate 2 (FruA E.C. 4.1.2.13), D-tagatose 1,6-bisphosphate 4 (TagA E.C. 4.1.2.40), L-fuculose 1-phosphate 5 (FucA, E.C. 4.1.2.17), and L-rhamnulose 1-phosphate 4 (RhuA, E.C. 4.1.2.19). From previous studies, we have DHAP aldolases with all four possible specificities readily available, we have demonstrated their broad substrate tolerance for variously substituted aldehydes, and we have investigated their stereoselectivity profile with non-natural substrates [3-6]. 

The substrate spectrum of SuSyl from yeast is well documented for a variety of acceptors [24, 29, 30]. In the series of ketoses we concluded that SuSyl favors the 3S,4R configuration because L-sorbose 4 and D-xylulose 5 are accepted and D-tagatose 6, D-psicose 7, and D-sorbose 8 are not substrates (Fig. 2.2.6.1 and... 

The ketoses D-tagatose 6 (43% relative activity) and D-ribulose 28 (24% relative activity) were identified as new acceptor substrates they are not accepted by recombinant SuSyl from yeast. However the acceptance for D-xylulose 5 is lost. The most significant changes were observed for the aldoses tested L-arabinose 14, D-xylose 12, and D-lyxose 11 are better substrates than D-fructose, with relative activities of 490%, 300%, and 151%, respectively. In the hexose series L-glucose 29 and L-rhamnose 30 were identified as new acceptor substrates, whereas the acceptance for D-and L-mannose, 16 and 21, was improved (Fig. 2.2.6.5) (Sauerzapfe and Elling, unpublished results). 

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