Glucose glycolytic pathway

Two and twelve moles of ATP are produced, respectively, per mole of glucose consumed in the glycolytic pathway and each turn of the Krebs (citrate) cycle. In fat metaboHsm, many high energy bonds are produced per mole of fatty ester oxidized. Eor example, 129 high energy phosphate bonds are produced per mole of palmitate. Oxidative phosphorylation has a remarkable 75% efficiency. Three moles of ATP are utilized per transfer of two electrons, compared to the theoretical four. The process occurs via a series of reactions involving flavoproteins, quinones such as coenzyme Q, and cytochromes. 

In most animal, plant, and microbial cells, the enzyme that phosphorylates glucose is hexokinase. Magnesium ion (Mg ) is required for this reaction, as for the other kinase enzymes in the glycolytic pathway. The true substrate for the hexokinase reaction is MgATP. The apparent K , for glucose of the animal... 

The second half of the glycolytic pathway involves the reactions that convert the metabolic energy in the glucose molecule into ATP. Altogether, four new ATP molecules are produced. If two are considered to offset the two ATPs consumed in phase 1, a net yield of 2 ATPs per glucose is realized. Phase II starts with the oxidation of glyceraldehyde-3-phosphate, a reaction with a large... 

The glycolytic pathway described in this chapter begins with the breakdown of glucose, but other sugars, both simple and complex, can enter the cycle if they can be converted by appropriate enzymes to one of the intermediates of glycolysis. Figure 19.32 shows the mechanisms by which several simple metabolites can enter the glycolytic pathway. Fructose, for example, which is pro-... 

Determine the anticipated location in pyruvate of labeled carbons if glucose molecules labeled (in separate experiments) with " C at each position of the carbon skeleton proceed through the glycolytic pathway. 

Mature red blood cells do not have nuclei, mitochondria, or microsomes therefore red blood cell function is supported through the most primitive and universal pathway. Glucose, the main metabolic substrate of red blood cells, is metabolized via two major pathways the Embden-Meyerhof glycolytic pathway and the hex-ose monophosphate pathway (Fig. 1). Under normal circumstances, about 90% of the glucose entering the red blood cell is metabolized by the glycolytic pathway and 10% by the hexose monophosphate pathway. 

Thus, D-fructose can be synthesized by a reversal of the Embden-Meyer-hof glycolytic pathway (see Fig. 2) in animals and in many other organisms. Unless evidence is available to the contrary, it is generally assumed that this pathway is present in any organism, since distribution studies indicate the system is ubiquitous. However, a different pathway is used by Pseudomonas saccharophila, which utilizes one mole of D-glucose or D-gluconic acid... 

The resting adult human brain consumes around 80 mg of glucose and 50 ml of 02 per minute, and once the glucose has been transported across the plasma membrane it is rapidly phosphorylated by hexokinase, the first enzyme of the glycolytic pathway. Hexokinase... 

The first reaction vi (Gx. ATP) describes the upper part of glycolysis, converting one (external) molecule of glucose (Gx) into two molecules of triosephosphate (TP), using two molecules of ATP. The second reaction v2 (TP, ADP) describes the synthesis of two molecules ATP from each molecule of TP. The third reaction v3 (ATP) describes a (lumped) overall ATP utilization. To obtain a minimal kinetic model for the glycolytic pathway, we adopt rate function similar to [96], using... 

We now turn to the metabolic fate of these sugars, fit most cells, the metabolic pathway responsible is termed glycolysis or the glycolytic pathway. The starting point for glycolysis is D-glucose. The end products of glycolysis... 

A central consequence of glycolysis is the production of limited quantities of ATP, the energy currency of the cell. Specifically, the sum total of the glycolytic pathway from D-glucose to lactate is ... 

The glycolytic pathway, or glycolysis, is a metabolic sequence in which glucose is broken down to pyruvic acid. The subsequent fate of pyruvate then depends upon whether or not the organism is aerobic or anaerobic Under aerobic conditions, pyruvate is oxidized via oxidative phosphorylation under anaerobic conditions, pyruvate is converted further into compounds such as lactate or ethanol, depending upon the organism. 

By combining the glycolytic pathway, the Krebs cycle, and oxidative phosphorylation, the energy yield from the aerobic degradation of glucose will be... 

Scheme 9.4 Biochemical retrosynthesis of 2 -deoxyribo-nucleosides from glucose, acetaldehyde and a nucleobase (adenine) through the glycolytic pathway and the reverse reactions of 2 -deoxyribonucleoside degradation.

Scheme 9.5 Multi-step enzymatic process for 2 -deoxyribo-nucleoside production from glucose, acetaldehyde and a nucleobase through glycolysis, reverse reactions of 2 -deoxy-ribonucleoside degradation and ATP regeneration by the yeast glycolytic pathway recycling the phosphate generated by nucleoside phosphorylase.

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