EMIL project

Current address EMIL Project, Fujitsu Kansai Systems Laboratory, 2-2-6 Shiromi, Chuoku, Osaka 540, Japan... 

Because carbohydrates usually have numerous chirality centers, it was recognized long ago that a quick method for representing carbohydrate stereochemistry is needed. In 1891, Emil Fischer suggested a method based on the projection of a tetrahedral carbon atom onto a flat surface. These Fischer projections were soon adopted and are now a standard means of representing stereochemistry at chirality centers, particularly in carbohydrate chemistry. 

For a thorough understanding of stereochemistry, it is useful to examine molecular models (like those depicted in Fig. 4.1). However, this is not feasible when writing on paper or a blackboard. In 1891, Emil Fischer greatly served the interests of chemistry by inventing the Fischer projection, a method of representing tetrahedral carbon atoms on paper. By this convention, the model is held so that the two bonds in front of the paper are horizontal and those behind the paper are vertical. 

As already mentioned, the glucoamylase project was chosen to illustrate Emil Fischer s lock and key concept for enzyme specificity. It is seen that his vision has become unequivocally established. Many other developments could have been chosen, as can be appreciated from recent reviews by Hehre (54) and by Svensson (55). Comforth (56) provided a fine overview of asymmetry and enzyme action in his Nobel prize lecture. Noteworthy is the conclusion that stereospecificity is something not just incidental, but essential to enzyme catalysis. In other words, the key must fit the lock. 

Filamin 370 Filaria worms 24 Fimbriae 6. See also Pili Fingerprinting. See also Peptide mapping of DNA 259 of proteins 118, 360 First Law of Thermodynamics 282 First order reactions 457 Fischer, Edmond H. 84 Fischer, Emil H. 42, 83 Fischer projection formula 42 of monosaccharides 163 FK506 488 Flagella... 

In the initial confusion, it was the great achievement of Emil Fischer to disengage himself from Van t Hoff s method of writing configurational formulas, and to go back to the ordered tetrahedral models themselves, for which he had to invent a projection of the steric arrangement onto the plane of depiction. 

Most of the carbon atoms in sugars have a tetrahedral geometry. Therefore, sugar molecules are not flat, but have a three-dimensional structure. The three-dimensional structure of carbohydrates is commonly depicted using Fischer projections, named in honor of Emile Fischer. Fischer worked out the structures of most of the carbohydrates in the first part of the twentieth century with little... 

If this model were compressed into two-dimensional space, we would get the projection shown in Fig. 27.6c. This is termed a Fischer projection and is named after a pioneer in stereochemistry, Emile Fischer. The Fischer projection has the following requirements ... 

At the turn of the twentieth century, Emil Fischer was studying the stereochemistry of sugars (Chapter 23), which contain as many as seven asymmetric carbon atoms. To draw these structures in perspective would have been difficult, and to pick out minor stereochemical differences in the drawings would have been nearly impossible. Fischer developed a symbolic way of drawing asymmetric carbon atoms, allowing them to be drawn rapidly. The Fischer projection also facilitates comparison of stereoisomers, holding them in their most symmetric conformation and emphasizing any differences in stereochemistry. 

Emil Fisoher (1852-1919), discovered phenyl-hydrazine as a PhD student In 1875, succeeded Hofmann at Berlin in 190Qwhdre he built the then largest chemical institute in the world, end was awarded the Nobel prize in 1902. As well as his work on indexes, he laid thd foundations of carbohydrate chemistry by completing the structure and synthesis of the main sugars, if only he hadn t also invented Fischer projections ... 

Both Fischer projections and the Kiliani-Fischer synthesis are named after Emil Fischer, a noted chemist of the late nineteenth and early twentieth centuries, who received the Nobel Prize in Chemistry in 1902 for his work in carbohydrate chemistry. Fischer s most elegant work is the subject of Section 27.11. 

It is sometimes useful to be able to draw a schematic diagram of the stereochemistry around a chiral carbon, especially when a molecule contains more than one chiral centre. The German chemist Emil Fischer solved this problem and his method of representing chiral centres is now called a Fischer projection. 

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