Hexose sugars direct

The polarognqihic bdiaviours of a variety of deoxy-sugars has been conqKued with those of their parent D-pentoses and -hexoses. The direct current polarographic determination of sugars as their aldimines proved suitable for kinetic measurements and the monitoring of syntheses. ... 

The initial HMF content in all honey samples was lower than the allowed maximum limit of 40 mg/kg as recommended by Turkish Alimentarus Codex [17], for honey in general. These results contradict the observation made by some authors that the types of honey produced in subtropical climates have high HMF exceeding 40 mg/kg [18]. However, the European Union council directive also allows for a maximum of 80 mg/kg for honey from tropical climates. The HMF level in honey is said to depend on the type of sugar present in honey and the fructose glucose ratio [19]. The HMF formation results from the acid catalyzed dehydration of hexose... 

The individual pathways of carbohydrate metabolism in plants overlap extensively they share pools of common intermediates, including hexose phosphates, pentose phosphates, and triose phosphates. Transporters in the membranes of chloroplasts, mitochondria, amyloplasts, and peroxisomes mediate the movement of sugar phosphates between organelles. The direction of metabolite flow through the pools changes from day to night. 

Pentose phosphate pathway Summary of the path way Reduced coenzymes produced by the pathway PENTOSE PHOSPHATE PATHWAY (p. 143) Also called the hexose monophosphate shunt, or6-phosphogluconate pathway, the pentose phosphate pathway is found in all cells. It consists of two irreversible oxidative reac tions followed by a series of reversible sugar-phosphate interconversions. No ATP is directly consumed or produced in the cycle, and two NADPH are produced for each glu cose 6-phosphate entering the oxidative part of the pathway. 

In vivo, pyruvate lyases perform a catabolic function. The synthetically most interesting types are those involved in the degradation of sialic acids or the structurally related octulosonic acid KDO, which are higher sugars typically found in mammalian or bacterial glycoconjugates [62-64], respectively. Also, hexose or pentose catabolism may proceed via pyruvate cleavage from intermediate 2-keto-3-deoxy derivatives which result from dehydration of the corresponding aldonic acids. Since these aldol additions are freely reversible, the often unfavourable equilibrium constants require that reactions in the direction of synthesis have to be driven by an excess of one of the components, preferably pyruvate for economic reasons, in order to achieve a satisfactory conversion. 

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