Embden-Meyerhof

Metabolic Functions. The formation of phosphate esters is the essential initial process in carbohydrate metaboHsm (see Carbohydrates). The glycolytic, ie, anaerobic or Embden-Meyerhof pathway comprises a series of nine such esters. The phosphogluconate pathway, starting with glucose, comprises a succession of 12 phosphate esters. 

In contrast with the well-known Embden-Meyerhof-Pamass glycolysis pathway for the conversion of hexose sugars to alcohol, the steps in conversion of ethanol to acetic acid remain in some doubt. Likely, ethanol is first oxidized to acetaldehyde and water (39). For further oxidation, two alternative routes are proposed more likely, hydration of the acetaldehyde gives CH2CH(OH)2, which is oxidized to acetic acid. An alternative is the Cannizzaro-type disproportionation of two molecules of acetaldehyde to one molecule of ethanol and one molecule of acetic acid. Jicetobacter... 

Yeast (qv) metabolize maltose and glucose sugars via the Embden-Meyerhof pathway to pymvate, and via acetaldehyde to ethanol. AH distiUers yeast strains can be expected to produce 6% (v/v) ethanol from a mash containing 11% (w/v) starch. Ethanol concentration up to 18% can be tolerated by some yeasts. Secondary products (congeners) arise during fermentation and are retained in the distiUation of whiskey. These include aldehydes, esters, and higher alcohols (fusel oHs). NaturaHy occurring lactic acid bacteria may simultaneously ferment within the mash and contribute to the whiskey flavor profile. 

All overview of the glycolytic pathway is presented in Figure 19.1. Most of the details of this pathway (the first metabolic pathway to be elucidated) were worked out in the first half of the 20th century by the German biochemists Otto Warburg, G. Embden, and O. Meyerhof. In fact, the sequence of reactions in Figure 19.1 is often referred to as the Embden-Meyerhof pathway. 

Embden-Meyerhof pathway (Section 29.5) An alternative name for glycolysis. 

Elimination reaction, 138. 383-393 biological examples of, 393 summary of, 393-394 Embden-Meyerhof pathway, 1143-1150 see also Glycolysis... 

The metabolic pathway for bacterial sugar fermentation proceeds through the Embden-Meyerhof-Paranas (EMP) pathway. The pathway involves many catalysed enzyme reactions which start with glucose, a six-carbon carbohydrate, and end with two moles of three carbon intermediates, pyruvate. The end pyruvate may go to lactate or be converted to acetyl CoA for the tricarboxylic acid (TCA) cycle. The fermentation pathways from pyruvate and the resulting end products are shown in Figures 9.7 and 9.8. 

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. 

Defects in the Embden-Meyerhof Pathway 3.2.1. Hexokinase Deficiency... 

For many years, it was considered that the Embden-Meyerhof pathway was the major route of carbohydrate metabolism in a wide variety of organisms. However, evidence has been slowly accumulated to suggest that alternative routes exist. 

The oxidative pathway for the metabolism of D-glucose 6-phosphate (XLV), distinctive from the glycolytic, Embden-Meyerhof route (see p. 200) and known as the hexose monophosphate shunt, was suggested by certain experiments of Warburg,200 Gerischer,207 Lipmann,208 and Dickens209... 

Al. Abraham, S., Cady, P., and Chaikoff, I. L., Effect of insulin in vitro on pathways of glucose utilization other than Embden-Meyerhof in rat mammary gland, y. Biol. Chem. 224, 955-962 (1957). 

It is difficult to realize that there were still unknown reactions in the glycolytic (Embden-Meyerhof) pathway until World War II. One of the then standard biochemistry texts (Thorpe) summarized the position in the 1938 edition as ... 

You will probably be familiar with glycolysis (the Embden-Meyerhof pathway, Figure 1.20) from previous studies at school perhaps, so let s use this important pathway to illustrate some points in the recommended strategy. 

One approach to compartmentalize hemoglobin is to encapsulate hemoglobin in biodegradable polymer-PEG-polylactide (30). These nanocapsules have a diameter of 80-150 nm and contain superoxide dismutase, catalase, carbonic anhydrase, and other enzymes of Embden-Meyerhof pathway that are needed for long-term function of an oxygen carrier (31,32). The polylactide capsules are metabolized in vivo to water and carbon... 

With the advent of PM3, biochemical reactions, for example, those involved in the Embden—Meyerhof pathway, can be studied. Until now, systems such as glucose-6—phosphate were either poorly represented, or were prohibitively slow to calculate. 

A major route of breakdown of carbohydrates is the Embden-Meyerhof-Parnas pathway, often referred to simply as glycolysis. It is indicated on the left side of Fig. 10-1 and in more detail in Figs. 

Figure 10-3 Coupling of the reactions of glycolysis with formation of lactic acid and ethanol in fermentations. Steps a to g describe the Embden-Meyerhof-Parnas pathway. Generation of 2 ATP in step b can provide all of the cell s energy.

Figure 17-9 Reaction sequences in fermentation based on the Embden-Meyerhof-Parnas pathway. Oxidation steps (producing NADH + H+) are marked "O" reduction steps (using NADH + H+) are marked "R."...

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