Double recognition models

Double Heck reaction, 42 494 Double layer interface, 30 223-225 Double nucleophilic displacement, capped cyclodextrin, 32 437 Double-pulse method, 38 31 Double recognition models, 32 451 52 Doublet mechanisms, 30 43, 45, 47 Drago parameters, 38 212 Drougard-Decrooq equation, 30 345, 356, 371 Dry evaporation, perovskite preparation, 36 246-247... 

Guest Binding of /3-Cyclodextrin and Double Recognition Model ... 

Enzyme models 18 and 19, which catalyze the decarboxylation, are typical examples of double recognition (87). These metalloenzyme models recognize a-ketoacid as the specific substrate by the hydrophobic interaction and coordination interaction as shown in Fig. 24 and Table XVII. Thus, the presence of the second recognition site, triamino-Zn2+, results in an increase... 

A double exponential model presented with Equation (32.3) is proposed for this response. The model implies the existence of a heterogeneous population of cells, which can be roughly divided into two subpopulations, differing in the rate of cell reaction to the toxin exposure. It is interesting to note that the visual appearance of fast responding cells ( star-like cells) and slow responding cells ( sheet-like cells) can be easily discriminated under microscope and with the aid of the shape-recognition software. 

Scheme 6.8 Epoxide recognition for epoxide hydrolase that detoxify living cells by catalyzing alcoholysis to water soluble diols. The working model involves the phenolic H-atoms of two tyrosines activating the epoxide for nucleophilic attack. This principle is realized analogously by double hydrogenbonding thiourea catalyst 9 in the natural medium water.

Series of various mono,- bi-, and poly-(thio)urea-functionalized (poly)saccha-rides have already been synthesized and studied for molecular recognition of, e.g., dimethyl and phenylphosphate as model compounds for monoanionic and polyanionic phosphate esters, respechvely [111]. Thiourea derivatives such as 195-197 were analyhcally identified to provide double hydrogen bonding mediated host-guest complexes of well-defined dimension and orientations and were also reported to serve as phosphate binders even in the hydrogen bonding environment of water (Figure 6.57) [111]. 

Stereoview of the polymerase active site of HIV-1 RT [38]. The amino acid residues that compose the putative dNTP-binding site, including the three catalytically essential aspartic acids, are shown with side chains. The double-stranded nucleic acid is shown with the atomic model in the HIV-1 RT/DNA/Fab complex. The dNTP-binding site consists of structural elements from both protein and nucleic acid. The precise composition, position, and conformation of the template-primer can affect the recognition of... 

Fig. 32 Enantiospecific recognition between the nucleic acid base adenine and the amino acid phenylglycine on Cu(110) [102]. a STM image (15nmxl0nm) of coadsorbed S-phenylglycine and alanine. Only the CW-rotated adenine double rows, marked by arrows, are decorated with S-phenylglycine double rows, b Structure model superimposed on the STM image of adenine/S-phenylglycine. The carboxylate oxygens and the N atom have been placed atop Cu atoms. Reprinted with permission of the authors...

DNA cross-links [53] [54] [146], In vivo evidence for this model was provided by yeast double mutants. In this system the differential cisplatin sensitivity caused by inactivation of Ixrl was directly related to damage recognition and formation of the excision repair complex [140]. 

In a separate study, pharmacokinetic-pharmacodynamic modeling of the psychomotor and amnesic effects of a single oral dose of lorazepam 2 mg was investigated in 12 healthy volunteers in a randomized, double-blind, placebo-controlled, two-way, crossover study using the following tasks choice reaction time, immediate and delayed cued recall of paired words, and immediate and delayed free recall and recognition of pictures (12). The delayed recall trials were more impaired than the immediate recall trials similar observations were made with the recognition versus recall tasks. 

The recognition of chiral carbonyl compounds, especially the substrates having a chiral stereogenic center at the a-carbon, have been a main subject of research for long time [81], since Curtin [82] and Cram [83] initially proposed a structural model for the diastereoselective addition to these molecules. There are in-depth studies related to this subject including chiral enolate addition, i.e., double asymmetric synthesis [84]. In this section, therefore, some other impressive topics of current interest are discussed briefly. 

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