Key-lock principle

The supramolecular complex 54 nicely embodies Emil Fischer s key-lock principle [36] for molecular recognition with the macrocycle being the lock and the monoamide taking the part of the key in a well-defined unique orthogonal arrangement (Figure 23). 

This abstraction is based on the key-lock principle introduced by Emil Fischer in 1894. According to this principle, the interaction of a biological entity with a molecule is best when both species behave like a key and a lock. If we now extend this principle to pharmaceuticals, then the drug molecule is the key. Certain... 

Emil Fischer (1852-1919) introduced the key-lock-principle (specific binding between enzyme... 

The underlying principle of the analytical methods described in this chapter is that of biomolecular recognition the ability of a biomolecule to interact with one other particular type of biomolecule, like a key fitting a lock. With this key-lock principle, it is possible to specifically detect the target molecule, which could be an antigen, an antibody, a hormone, a DNA fragment or a sugar, even in very complex sample mixtures like urine or untreated blood. 

Crown ethers with exocyclic multiple bonds and a cavity filled by metal ions would be a potential monomer of this type. The cavity can be considered as a polydentate chelate node. The nature of the cation and the size of athe macrocyclic cavity play an important role (the key-lock principle) [53]. There are reports of the production of such monomers from alkali metals and 4 -vinylmonobenzo-18-crown-6, (81), 4 -vinyldibenzo-18-crown-6 (82), and 4 -vinylbenzo-15-crown-5 (83). 

The active sites in enzymes are transition metal (TM) complexes which are responsible for the catalytic activity. Such complexes are surrounded by a protein mantle, which is rigid or flexible and is responsible for the regioselectivity. They operate via the key-lock principle (equation I). 

A different fit of the two enantiomers into the asymmetric cavities—the key-lock principle—of these polymers effects separation of the antipodes. For optimal enantioselectivity the secondary structure of the chiral spatially fixed matrix is decisive. This type of separation is usually called inclusion chromatography. 

Fischer formula, 4 697 a-Ketoxime, reduction, 2 572 Kettle soap making, 22 723, 736-737 Kettle-type reboilers, 79 510 Kevlar, 70 211, 212 79 742 20 79, 399 TD resins in, 22 589 Kevlar fibers, 73 373-376 26 760 Kew laboratories, 77 248—249 Key-and-lock principle, 7 574 Keyword-in-context (KWIC) index, 78 239 KF alumina, 5 337 Kharasch process, 79 114 Kidney, citric acid in, 6 632t Kidney Disease Outcome Quality Initiative (K/DOQI), 26 823 Kidney failure, 26 813 Kidney function, normal, 26 813 Kielselguhr 22 402... 

In the middle of the last century, synthesis techniques were develop>ed that enabled the fabrication of well-defined and highly regular micropwrous silica materials, such as zeolites, with pore sizes comparable to the size of the molecules one would like to catalyze . The appropriate matching of size and shape of these micropores with shape and size of reactant, intermediate or product molecules has been demonstrated to be an important factor in the control of catalytic p>erformance. This is analogous to the lock and key reactivity principle which was developed in the early part of the last century as a way to describe the activity of enzymes, the biochemical proteins in living systems. This process involves matching the shape and size of the catalytic cavity with that of the reactant molecules. 

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

Case, John. The wards of the key to Helmont proved unfit for the lock, or, The principles of Mr. William Bacon examined and refuted, and the honour and value of true chymistry asserted. London Printed for the author and are to be sold by John Smith bookseller in Russel-street in Covent-Garden, 1682, 1682. [4], 24 p... 

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... 

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