Embden

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. 

Elucidation of the glycolysis process (by G. Embden and by O. Meyerhof) followed by the glucose oxidation process (H. A. Krebs. 1937) established the intimate involvement of P compounds in miiny biochemical reactions. 

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... 

Microorganisms under anaerobic growth conditions have the ability to utilise glucose by the Embden-Mereyhof-Parnas pathway.4 Carbohydrates are phosphorylated through the metabolic pathway the end products are two moles of ethanol and carbon dioxide.5... 

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. 

Rg. 9.8. Fermentation of glucose to acetate or lactate via the Embden-MeyerhofF-Pamas pathway. 

Eadie-Hofstee plot, 111 Electrode, 14, 15, 72, 73, 75-80 Electrodialysis, 351, 353-356, 393 Elemental composition, 228-230 Embden-Myerhof-Pamas pathway (EMP), 3, 207, 244-251... 

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... 

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... 

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... 

Rafii F, Moore JD, Ruseler-van Embden JGH, Cemiglia CE (1995) Bacterial reduction of azo dyes used in foods, drugs and cosmetics. Microecol Ther 25 147-156... 

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). 

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