Stereoselectivity receptors

A. Example of an enantiomeric pair with different affinity for a stereoselective receptor... 

Kd of drug binding to receptor (1-100 nM) binding reversible and stereoselective Receptors saturable because of finite number... 

Surface monolayers on water, metals, silica or organic polymers do also not only self-organize or self-assemble , but they can be selectively functionalized as well with dyes, stereoselective receptors or nanoholes. Several monolayers can also be synkinetized subsequently to form redox chains with different electron donors or acceptors in multilayers. Vectorial reaction chains can thus be materialized in synkinetic materials. 

Keywords Receptors Receptor history Paul Ehrlich John Newton Langley Emil Fischer Louis Pasteur Drug-receptor interactions Stereoselectivity Receptor diseases Receptor regulation Receptor structure... 

Astemi2ole (10) has further been modified into a series of 4-phenylcyclohexylamine compounds, resulting in the synthesis of cabastine, for example. Cabastine is a highly active compound and its geometric isomers are also active, demonstrating the stereoselectivity of histamine receptors toward chiral ligands. The > S, 4 R-levo antipode of cabastine was the most active, and therefore this isomer, levocabastine (13), has been chosen for further development. Because of high potency, levocabastine has been developed for topical appHcation such as eye drops and nasal spray. 

Although estrone and estradiol (26) have both been isolated from human urine, it has recently been shown that it is the latter that is the active compound that binds to the so-called estrogen receptor protein. Reduction of estrone with any of a large number of reducing agents (for example, any of the complex metal hydrides) leads cleanly to estradiol. This high degree of stereoselectivity to afford the product of attack at the alpha side of the molecule is characteristic of many reactions of steroids. 

In earlier proposals (Anderson et al. 1978), based on this stereoselectivity for the S enantiomer of MDMA, it was suggested that, rather than having a direct effect at serotonin receptors, perhaps MDMA was a neurotransmitterreleasing agent, acting in a fashion similar to amphetamine, for which the S enantiomer is also more active than the R enantiomer. A subsequent study... 

Stereoselectivity was evident in the assays for stereotyped behavior and PCP receptor interaction, but not in the assay for ataxia as the (+) isomers of the PCP-like drugs and SKF-10,047 were more potent than the (-) isomers in induction of stereotyped behavior and inhibition of binding of 3H-PCP. However, one exception to this trend is that the (-) isomer of cyclazocine was more potent than the (+) isomer in industion of stereotyped behavior and inhibition of the binding of 3H-PCP. 

The pharmacological properties of the cloned opiate receptors are similar to the characteristics of the endogenously expressed receptors [9, 36, 45]. The binding of opiates to the cloned receptors is stereoselective and the antagonist naloxone interacts with all three of the cloned receptors, although naloxone had much lower af-... 

NU(C) base atoms (5) The stereoselectivity of the BPDEs during intercalative covalent binding in kinked DNA and (6) The possible reorientation of the complex to yield an externally bound adduct. The energetics for each of these processes will be presented to identify the important steps that influence the binding of specific isomers. It will be shown that the orientation of each diastereoisomer of BPDE about specific base atoms in kinked receptor sites in the duplex DNA during covalent bond formation is the determining factor in stereoselectivity. 

Although we postulate that this receptor site results in stereoselectivity, it may not be the final state. The orientation of the long axis of the pyrene moiety is approximately 80°-90° and this implies quasi-intercalation of site IQ (56-58). The kinked site proposed by Hogan et al. (50) and studied by Taylor and Miller (MO for l(+)-N2(G) binding in retrospect appears to represent different binding sites. The orientation of the pyrene moiety of a(BPDE) = 1+3° and the local DNA axis in the kink of y(DNA) = 29° (50) will be explained by external binding in the next section. The intercalative covalent binding in a kinked site is an intermediate step between intercalation and the final structure for the externally bound BPDE-N2(G) adduct, but it becomes the final structure for the quasi intercalated BPDE-N6(g), 06(g) and N +(c) adducts. 

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