Fischers Lock and Key

First law of thermodynamics, 24 645-648 First limiting amino acid, 2 601 First-order irreversible chemical kinetics, 25 286-287, 292-293 First-principle approach, in particle size measurement, 13 153 First sale doctrine, 7 793 Fischer, Emil, 16 768 Fischer carbene reaction, 24 35-36 Fischer esterification, 10 499 Fischer formula, 4 697 Fischer-Indole synthesis, 9 288 Fischer lock and key hypothesis, 24 38 Fischer-Tropsch (FT) synthesis, 6 791, 827 12 431... 

Fig. 2. Principle mechanisms of formation of a receptor—substrate complex (a) Fischer s rigid "lock-and-key" model (b) "induced fit" model showing...

The problem of molecular recognition has attracted biologically oriented chemists since Emil Fischer s lock-and-key theory l0). Within the last two decades, many model compounds have been developed micelle-forming detergents11, modified cyclodextrins 12), many kinds of crown-type compounds13) including podands, coronands, cryptands, and spherands. Very extensive studies using these compounds have, however, not been made from a point of view of whether or not shape similarity affects the discrimination. 

Early in the last century, Emil Fischer compared the highly specific fit between enzymes and their substrates to that of a lock and its key. While the lock and key model accounted for the exquisite specificity of enzyme-substrate interactions, the imphed rigidity of the... 

HOW EMIL FISCHER WAS LED TO THE LOCK AND KEY CONCEPT FOR ENZYME SPECIFICITY1... 

At this point Fischer concluded that the enzymes, in terms of the configurations of the substrates, are as fastidious as yeast and other organisms. He then returned to the above-mentioned hypothesis that he and Thierfelder had proposed (30) and concluded (32) that the protein substances known as invertin and emulsin, like the substrates whose hydrolyses they effected, were asymmetrically formed molecules. On the basis of this consideration, he came to the momentous lock and key concept for enzyme activity and commented as follows ... 

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. 

Enzymic methods in preparative carbohydrate chemistry, 49, 175-237 Enzyme specificity, how Emil Fischer was led to the lock and key concept for, 50, 1-20... 

Lemieux and Spohr (Alberta) here trace our understanding of enzyme specificity in broad perspective as they assess Emil Fischer s lock and key concept advanced a century ago in relation to current ideas of molecular recognition. It may be noted that the very first article in Volume 1 of Advances, by Claude S. Hudson, was devoted to the Fischer cyanohydrin synthesis and the consequences of asymmetric induction. 

The initial steps in enzyme-catalysed reactions involve the binding of the reactants to the enzyme surface and one of the functions of the enzyme is to orientate these reactants relative to each other. This idea was suggested by Fischer as a lock-and-key hypothesis, where the enzyme is the lock and the... 

The "lock-and-key" description of the catalytic action of enzymes given by Emil Fischer [13] one hundred years ago, put more emphasis on the enzyme-substrate specificity than on stereospecificity, suggesting the idea of ... 

One of the earliest, simplest, and best-known examples of this concept is the lock-and-key model of enzyme action hrst proposed by German chemist Emil Fischer (1852-1919) in 1894. While it has been significantly modihed since that time, the general mode of action suggested by Fischer is probably generally correct for most types of enzyme action. According to the lock-and-key model, illustrated below. 

An understanding of enzyme action requires not only a knowledge of pathway and rates, but also an explanation of specificity. The dominant idea in this area was that of Emil Fischer, who described the enzyme-substrate complex in terms of lock and key (Fischer, 1894). In essence, Fischer presented a steric model where a cavity in the enzyme was assumed to be shaped to fit the substrate and to hold it firmly in place. This model served enzymologists well for decades and helped them to visualize the interactions between specific... 

One way in which this condition might be fulfilled would be if the molecules when combined with the enzyme, lay slightly further apart than their equilibrium distance when [covalently joined], but nearer than their equilibrium distance when free. Using Fischer s lock and key simile, the key does not fit the lock quite perfectly but exercises a certain strain on it. 

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