Sugars mechanism

Epimerization of sugar, mechanisms 778 Epimers, definition of 163 Epinephrine (adrenaline) 542,553, 553s Episomes. See plasmid Epithelial cells 29 Epitheliocytes 25 Epoxides, alkyation by 254 Epoxide hydrolases 591 EPR (electron paramagnetic resonance) spectroscopy 398, 399 of glutamate mutase 873 in study of phosphotransferases 639 EPSP (enolpyruvoylshikimate-3-phosphate) 687s... 

H. W. Liu Exploring nature s strategics for making unusual sugars mechanisms, pathways and biosynthetic applications... 

Plants also contain the enzymes necessary for interconverting the hexoses. The reactions shown in Fig. 6 represent some of the known pathways for these interconversions. When barley plants were infiltrated 71) with D-glucose, D-fructose, D-galactose, or D-mannose, sucrose accumulated hence the enzymes were present for interconverting these sugars. Mechanisms for these interconversions are discussed in several reviews 72 73) (see also Section 3B of this chapter). 

Dimethyl sulphate is of particular value for the methylation of phenols and sugars. The phenol is dissolved in a slight excess of sodium hydroxide solution, the theoretical quantity of dimethyl sulphate is added, and the mixture is heated on a water bath and shaken or stirred mechanically (compare Section IV, 104). Under these conditions only one of the methyl groups is utilised the methyl hydrogen sulphate formed in the reaction reacts with the alkali present. -... 

Sugar is destroyed by pH extremes, and inadequate pH control can cause significant sucrose losses in sugar mills. Sucrose is one of the most acid-labile disaccharides known (27), and its hydrolysis to invert is readily catalyzed by heat and low pH prolonged exposure converts the monosaccharides to hydroxymethyl furfural, which has appHcations for synthesis of glycols, ethers, polymers, and pharmaceuticals (16,30). The molecular mechanism that occurs during acid hydrolysis operates, albeit slowly, as high as pH 8.5 (18). 

Marketing. Most of the cocoa beans and products imported into the United States are done so by New York and London trade houses. The New York Sugar, Coffee, and Cocoa Exchange provides a mechanism by which both chocolate manufacturers and trade houses can hedge their cocoa bean transactions. Additional information on the functions of the New York Cocoa Exchange is available (3). 

Typical pilot-plant top-suspended baskets are 305 mm (12 in) diameter by 127 mm (5 in) deep. Commercial machines are available in sizes from 508-mm (20-in) diameter by 305-mm (l2-in) depth to 1524-mm (60-in) diameter by 1016-mm (40-in) depth and develop up to 1800g in the smaller and intermediate sizes. Except in the sugar apphcation, operation with a two-speed motor (half speed for loading and full speed for purging) is typical. Hydraulic drives with variable-speed capability are commonly used in the chemical industiy To maximize the number of cycles per hour, a combination of electrical and mechanical braking is employed to minimize the deceleration period, which is a transition period of no value to the process. 

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