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Volume 47, Issue 6
Displaying 1-11 of 11 articles from this issue
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Yukito MURAKAMI, Jun-ichi KIKUCHI1989 Volume 47 Issue 6 Pages 484-492
Published: June 01, 1989
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSHost-guest complexation behavior of various functionalized cyclophanes has been discussed in view of their efficiency as artificial receptors and enzymes. Hydrophobic cavities of simple and monocyclic cyclophanes are too small and shallow to allow effective inclusion of hydrophobic guests of various bulkiness, even though the primary hydrophobic binding interaction is further enhanced by electrostatic and charge-transfer interactions. In order to improve molecular recognition ability of cyclophanes, modifications of macrocyclic skeletons are required to give three-dimensionally extended hydrophobic cavities. One approach to create such sizable internal cavities is to construct cage-type macrocycles, e.g., cubic cyclophanes, which are capable of incorporating guest molecules through the lock-and-key mechanism. Another is to introduce multiple hydrocarbon chains into macrocyclic skeletons, e.g., octopus cyclophanes, so that the induced-fit binding is exercised. As regards simulation of coenzyme-dependent enzymatic reactions, coenzyme factors must be introduced into cyclophanes covalently or noncovalently. Under cooperation of an effective substrate-activation process that can be performed with vanadium trichloride and molecular oxygen, a real artificial holoenzyme system has been composed with an octopus cyclophane and a hydrophobic vitamin B12 The holoenzyme model system catalyzes various carbon-skeleton rearrangement reactions in a manner as observed for the naturally occurring enzymes.View full abstractDownload PDF (994K) -
Shigeki SASAKI, Kenji KOGA1989 Volume 47 Issue 6 Pages 493-502
Published: June 01, 1989
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSDuring the last two decades, the concept of molecular recognition has become to play a central role in chemistry. So-called host-guest chemistry employing crown ethers, cryptands and related hosts has contributed to the development of this concept. This review deals with molecular recognition by these hosts for 1) cations, 2) anions, 3) neutral molecules, and 4) chiral guests. And recent studies on their application to asymmetric synthesis and enzyme modeling are briefly summarized.View full abstractDownload PDF (1177K) -
Hiroshi IKEDA, Fujio TODA1989 Volume 47 Issue 6 Pages 503-513
Published: June 01, 1989
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSCyclodextrins (CDs) are a series of cyclic and nonreducing oligosaccharides produced by CGTase. They can form inclusion complexes with many kinds of molecules, and fundamental and applied investigations about CD are made in the many fields. CDs are successfully used in various industries, e.g., food, pharmaceutical, cosmetic, and toiletry. By modification of CD, properties of CD can be changed and poly-functional host molecule can be made.View full abstractDownload PDF (1246K) -
Hisanobu OGOSHI, Yasuhisa KURODA1989 Volume 47 Issue 6 Pages 514-522
Published: June 01, 1989
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSMolecular recognitions by use of porphyrin derivatives as host molecules are reviewed. Following three subjects are discussed in detail;
i) molecular recognitions on the porphyrins by the various types of space designs for environments around axial ligands, ii) molecular recognitions of functional groups on guest molecules by use of specific interactions between porphyrin hosts and guest molecules, iii) chiral molecular recognitions via introduction of chiralities into porphyrin rings or their functional groups.
In these sections, it is shown that the variety of molecular recognitions including multiple cooperative interactions have been realized by use of porphyrin derivatives. The most characteristic advantage of porphyrins as host molecules is that the positions and orientations of the functional groups can be controlled so precisely as to optimize the interactions operating between the host-guest couples, because of their rigid structures.View full abstractDownload PDF (984K) -
Takashi ARIMURA, Seiji SHINKAI, Tsutomu MATSUDA1989 Volume 47 Issue 6 Pages 523-534
Published: June 01, 1989
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSCalixarenes are cyclic oligomers synthesized from phenols and formaldehyde. We designed and synthesized a variety of new host molecules from calixarenes. They acted as cyclic ionophores with crown-like functions by introducing ionophoric groups. In particular, calix [5] arene and calix [6] arene with carboxylate groups acted as “super-uranophiles” exhibiting the record-breaking uranyl affinity (K=1018.4-19.2 M-1) and uranyl selectivity (1010.6-17). Inclusion of organic guest molecules in solution was effected for the first time by using water-soluble calixarenes which had either anionic, cationic, or neutral hydrophilic groups. Chiral, water-soluble calixarenes changed their conformation upon inclusion of guest molecules, which was conveniently detected by the CD spectra and provided several lines of important information for the host-guest-type complex formation. Through these studies, it was demonstrated that the moderate rigidity and the remaining conformational freedom are important characteristics of the complex formation with calixarene-based host-molecules.View full abstractDownload PDF (1461K) -
Yuichi ISHIKAWA, Toyoki KUNITAKE1989 Volume 47 Issue 6 Pages 535-546
Published: June 01, 1989
Released on J-STAGE: January 22, 2010
JOURNAL FREE ACCESSBilayer membranes are formed spontaneously by regular, cooperative, two-dimensional assemblage of component amphiphiles. The regular, coordinative molecular arrangements in bilayer are capable of complexing with guests specifically. In contrast to the general host-guest compounds such as crown ethers-M+ having convergent binding vectors, the bilayer-guest complexes have parallel or divergent binding vectors with regularity Bilayer itself is considered to be a new type of host compound. The concept of host-guest chemistry in bilayer system is on the basis of regularity of binding vectors. For the new concept to generalize, one must develop the investigations based on the characteristics of bilayer membrane.View full abstractDownload PDF (1712K) -
Reiko KURODA1989 Volume 47 Issue 6 Pages 547-556
Published: June 01, 1989
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSInteractions between DNA and DNA binding proteins, and between DNA and small biologically active molecules are central to many of the vital processes in biological systems. Two types of mode of DNA-ligand interactions, i.e., intercalation between the base pairs of DNA, and binding in the grooves of DNA, are reviewd, focusing on the structural aspects. DNA binding proteins include sequence non-specific gene 5 protein from bacteriophage fd and DNase I, as well as highly sequence specific restriction enzyme Eco RI. Effects of methylation on the recognition sequence will be discussed. Detailed interactions observed between the groove binding antibiotic netropsin and d (CGCGAATTCGCG) 2 or d (CGCGATATCGCG) 2 will be compared. Finally, our recent work on new DNA cleaving agents with groove preference is briefly mentioned.View full abstractDownload PDF (1266K) -
Isao KARUBE1989 Volume 47 Issue 6 Pages 557-567
Published: June 01, 1989
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSEnzyme, immuno, and microbial sensors have been developed and applied for clinical analysis, the process control and environmental monitoring.
Electrodes have been generally used as a transducer in biosensors, but attention is now focusing on sensors utilizing a semiconductor device as a transducer The use of semiconductor devices or microelectrodes enables the miniaturization of biosensors, consequently allows the measurement using only minute amount of samples and also the integration of several biosensors in one chip. Furthermore, the mass production of these devices and electrodes is also possible, hence the price of biosensors can be reduced. The reduction in price allows the development of disposable type microbiosensors. An ion sensitive field effect transistor (ISFET), a micro hydrogen peroxide electrode and a micro oxygen electrode were used as transducers for these microbiosensors. This paper deals recent progress in the development of biosensors and microbiosensorsView full abstractDownload PDF (1604K) -
Masahiro JOHNO, Atsuo FUKUDA1989 Volume 47 Issue 6 Pages 568-582
Published: June 01, 1989
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSFollowing an introduction to ferroelectric liquid crystal displays of Clark-Lagerwall type, an explanation is given to the effects of binary mixing on several properties, i.e. eutectic phenomena, phase sequences, the sign of spontaneous polarization and the handedness of helicoidal structure. Actual mixtures are introduced in view of obtaining a high speed response. The importance of avoiding the twisted states of director and the chevron structure of smectic layer is emphasized to attain high contrast with enough brightness. Finally, the tristable switching, recently observed in a group of materials, is explained and its usefulness is insisted.View full abstractDownload PDF (1668K) -
Eiichi KIMURA1989 Volume 47 Issue 6 Pages 583-594
Published: June 01, 1989
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSFuture development of host-guest chemistries (as described fully in the earlier sections) will be quite promising in the following functions
1. Selective and efficient uptake of more variety of guest ions and molecules by new hosts.
2. Selective separation, dissolution or transport of more variety of guests.
3. Information signalling or transmission by host-guest complexation or decomplexation.
4. Development of new functions as host-guest molecular aggregates.
5. New chemical reactions by host-guest complexes.
6. Host-guest interactions only upon external directions or stimulations.
Typicals of those currently developing cases (especially with macrocyclic polyamines and other unmentioned host molecules) are presented.View full abstractDownload PDF (986K) -
[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...1989 Volume 47 Issue 6 Pages 595-597
Published: June 01, 1989
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSDownload PDF (408K)
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