| 书目名称 | Proceedings of the First International Symposium on Cyclodextrins | | 副标题 | Budapest, Hungary, 3 | | 编辑 | J. Szejtli | | 视频video | http://file.papertrans.cn/759/758537/758537.mp4 | | 丛书名称 | Advances in Inclusion Science | | 图书封面 |  | | 出版日期 | Conference proceedings 1982 | | 关键词 | DNA; Ether; Protein; aromatic; chromatography; nuclear magnetic resonance (NMR); oxygen; polymer; purificati | | 版次 | 1 | | doi | https://doi.org/10.1007/978-94-009-7855-3 | | isbn_softcover | 978-94-009-7857-7 | | isbn_ebook | 978-94-009-7855-3 | | copyright | Springer Science+Business Media Dordrecht 1982 |
| 1 |
Cyclodextrin — A Paradigmatic Model |
F. Cramer |
|
Abstract
Since Emil Fischer’s postulate of the ‘lock and key’ specificity of enzymes with respect to substrates one tries to understand this specificity in terms of stereochemistry, interaction of specific groups, weak interactions, hydrophobic binding or rates of reactions. Even with the knowledge of the complete three-dimensional structure of many enzymes, their extremely high specificity in most cases is hard to understand. In this situation cyclodextrins have served as extremely useful models for enzyme like interactions even in an early stage of cyclodextrin research. They form stereospecific complexes. They can be used in order to separate enantiomers. They show hydrophobic interactions. They provide an inner surface with dielectric properties different from the outside solution. They show off- and on-rates in complex formation similar to those of enzymes. They can accelerate certain chemical transfer reactions to a considerable extent. Therefore during the past 30 years they have served as models for enzyme specificity, enzymatic catalysis, weak interactions, cavities in solution. They offer an ideal set of models and therefore in themselves they are models for models: paradigmatic models.
|
| 2 |
Cyclodextrin Research in Japan |
T. Nagai |
|
Abstract
A start in research of cyclodextrin (CDX) in Japan was actually made around the end of 1960’s. The activity in the research field has been enhanced since several chemical companies started to produce CDX of high quality and comparatively low price in a large scale around 19 71. As the application of CDX is expanding to various field, the price is expected to get cheaper in future, accompanying more active development in the research..Concerning the method of production of CDX, a CDX-producing enzyme was found recently from an alkalophilic bacteria of Bacillus genus. The other new approaches have also been made..As the safety of CDX has been confirmed, researches for pharmaceutical application are very active at the present as follows: solubilization, enhancement of absorption, suppression of irritation to stomach, and preparation of inclusion compounds with drugs. Solid inclusion compounds with drugs can be prepared by freeze-drying, cogrinding, and so on. The products of tablets and injections of prostaglandins included by CDX are now on market..In addition to such fundamental studies of CDX as on the formation mechanism and X-ray analysis of inclusion compounds, noticeable ones are made recently concerning an application of CDX or its derivatives to investigations for an understanding of enzymic or chemical reactions, for example, using capped CDX..Most recent representative researches in Japan are introduced here by the respective participants from Japan..We don’t forget the names of Villiers, Schardinger and Cramer and so on as the pioneers in researches of cyclodextrin (CDX). During the past twenty years, so many papers have been published concerning CDX. Actually, however, there was no remarkable contribution to these researches by Japanese workers at the early stage. Researches of CDX in Japan started really since the end of 1960’s by Kuge, Koizumi, and so on. Around that time, Matsutani Kagaku Kogyo Co. and CPC International Inc. started a production of β-CDX in a large scale. Now, Nihon Shokuhin Kako Co. produces CDX on the commercial basis in Japan. As the application of CDX is expanding to various fields, the price is expected to get cheaper in future, accompanying more active development in the research..It is very difficult for me to introduce here the whole works in CDX researches in Japan. Therefore, I like to talk about some examples of them.
|
| 3 |
Industrial Production of Cyclodextrins |
K. Horikoshi,N. Nakamura,N. Matsuzawa,M. Yamamoto |
|
Abstract
We isolated three alkalophilic bacteria producing large amount of cyclodextrin glycosyltransferases (CGTases). Two of the enzymes, CGTases of . No. 38–2 and . No. 17–1 were purified by starch adsorption and DEAE-cellulose chromatography followed by gel filtration. The enzymes were very thermostable, especially . No. 38–2 enzyme was not inactivated up to 70 C. The enzymes isolated converted about 65–80% of potato starch to cyclodextrins at 1% (w/v) substrate concentration. Through the CGTase of . No. 38–2, crystalline β-cyclodextrin, γ-cyclodextrin and a mixture of cyclic and acyclic dextrins were produced on an industrial scale plant without using any organic solvent. One ton of potato starch suspension (15% w/v) containing 10 mM CaCl. was liquefied by the CGTase at 90 С (pH 8.5) and then cooled to 60 C. The liquefite was readjusted to pH 8.5 with CaCO. and CGTase was added again. The cyclodextrin formation was maintained at 60 С for 45 h. After the reaction, the enzyme was inactivated at 80 C. The appreciable amount of bacterial α-amylase was added (pH 6.0) to hydrolyse saccharide which were not converted to cyclodextrin. The digest was decolorised and passed through ion exchangers. The refined digest was concentrated to 45% (w/v) and transfered to a crystallizer. The crystalline β-cyclodextrin was collected by centrifugation. The filtrate containing cyclodextrins is available as CH for food additives. From this CH, γ-cyclodextrin was produced. The CH was treated with gluco-anylase and passed through a Toyo Pearl HW-40 column to separate γ-cyclodextrin from other saccharides. The γ-cyclodextrin thus prepared was crystallised directly from water..In 1969, the authors started the investigation of alkalophilic microorganisms which grew well at high alkaline pH values ( pH 10–11 ). The microorganisms were isolated from soil by using alkaline media containing 1 % Nap.C0. ( 1 ). About 20 enzymes which are entirely new have been found by our method, which is called “ Alkaline Fermentation ” ( 2 ). The properties of the microorganisms isolated have been reported elsewhere. This paper deals with the isolation and purification of the new cyclodextrin glycosyltransferases ( CGTases ) produced by alkalophilic bacteria. Through one of these enzymes, production of cyclodextrins and a mixture of cyclic and acyclic dextrins on an industrial scale plant without using any kind of organic precipitant will be presented.
|
| 4 |
Process Development for the Production of α-Cyclodextrin |
E. Flaschel,J.-P. Landert,A. Renken |
|
Abstract
A process has been developed to utilize the highly active cyclodextrin-glycosyltransferase (CGT) from . M5 al for α-cyclodextrin (α-CD) production. To maximize the α-CD yield, decanol has been used to precipitate α-CD during the reaction. Thus, yields of 50–60% are obtained. Since the crystalline complex is easily separated and decanol can be stripped off efficiently by steam distillation, this process seems to be economically feasible. The α-CD produced can be used in the food industry.
|
| 5 |
The Preparation and Some Properties of Glucosyl-Cyclodextrins |
Shoichi Kobayashi,Keiji Kainuma,Dexter French |
|
Abstract
Glucosyl-cyclodextrins were prepared by the action of . cyclomaltodextrin glucanotransferase (BME)on branched dextrin of waxy corn starch prepared by removing the cyclodextrins with bromobenzene and tetrachloroethane from the BME-starch digest..Branched cyclodextrins were effectively produced by the action of BME on branched dextrin in the presence of SDS and were further degraded to glucosyl-cyclodextrins by the combined action of . α-amylase and glucoamylase. These enzymes also degrade β and γ-cyclodextrins, which interfere with the separation of glucosyl-cyclodextrins by paper-chromatography, to glucose..Glucosyl-cyclodextrins were separated by paperchromatography. Glucosyl-α-cyclodextrin was crystallized from water and made into a crystal complex with iodine. Glucosyl-cyclodextrins have extremely high solubility compared to the original cyclodextrins, solubilyze various kinds of oily substances in them and are extraordinary resistant to the action of . α-amylase.
|
| 6 |
Separation of Cyclodextrins with Gelchromatography and HPLC |
M. Szilasi,K. Otta,B. Zsadon,J. Szejtli,F. Tüdős |
|
Abstract
Previously, several chromatographic methods have been described for the separation of cyclodextrins. We elaborated a chromatographic method for analytical and for preparative separation of α-β- and γ-cyclodextrin on dextran gel(Sephadex) columns [1].
|
| 7 |
Rapid and Simple Spectrophotometric Method for Determination of Micro-Amounts of Cyclodextrins |
M. Vikmon |
|
Abstract
Cyclodeitrins are known to form inclusion complexes with many kinds of organic dye molecules..Phenolphtalein, the acid-base indicator forms stable colourless inclusion complexes with .-, .- and .-cyclo-dextrins in aqueous solutions at pH 10,5. Complex stability constants /K./ of the different CD-complexes cure: .. The molar ratio of phenolphtalein to any of the CDs is 1:1. The concentration range where the decrease of color intensity of phenolphtalein is proportional to CD concentrations was determined: .This method is also easily applicable to assort different batches of CD comparing the samples with standards..Cyclodextrins are known to form inclusion complexes with many kinds or organic dye molecules (l,2,3)..One of the most frequently used acid-base indicator, phenolphtalein forms a very stable colourless inclusion complex with .-cyclodextrin in 4. 10.M Na.CO. solution at pH 10,5. Stability constant /K./ was found to be relatively high, K. = 2,16. 10. M. and can be easily measured spectrophoto-metrically (4). . and .-cyclodextrin also form inclusion complexes with phenolphtalein under similar conditions but complex stability constants are very different from the one of .-cyclodextrin complex: .It must be mentioned that these stability constants were calculated using the commonly accepted and simple Benesi--Hildebrand method, because the concentrations of the components were not comparable, .-cyclodextrin and .-cyclodextrin were taken in high excess..Buvári and Barcza’s (4) calculation was based on the generally known relations of coordination chemistry because the concentrations of phenolphtalein and .-cyclodextrin were nearly identical. Their method delivered an indirect proof for the 1:1 ratio of components in the complex. The same 1:1 complex formation was assumed with .-and .-cyclodextrins too..In our measurements the concentration of phenolphtalein was 3. 10. M, concentrations of cyclodextrins were varied between 0-4. 10.M for .-cyclodextrin, 0-3. 10.M for .-cyclodextrin and 0-4. 10.M for .-cyclodextrin. The pH was supported by 4. 10.M Na.CO..
|
| 8 |
Enzymology of the Cyclodextrins |
H. Bender |
|
Abstract
The cyclization reaction is a special type of the 4-α-D-gluco-pyranosyltransfer reactions typical of the cyclodextrin glyco-syltransferases (CGTs). The enzyme from K.pneumoniae M 5 al simultaneously catalyzes cyclization and an acceptor-dependent transfer of linear fragments of 4-α-D-glucopyranosyl chains (disproportionation). Maximum cyclization rates are obtained with chain lengths of glc.-glc., indicating the dependence upon the helical conformation of the substrate. αCD is formed initially by most of the CGTs. The rates of βCD- and γCD-for-mation are extremely low. In contrast to αCD the higher CDs scarcely participate in reverse reactions and, therefore, accumulate. Only the incubation time determines which CD is obtained as the main cyclic product. By shifting the reaction equilibrium in the cyclization direction the yields of CDs can be enlarged significantly. Using an ultra-/diafiltration reactor, 70% of starch (enzyme-substrate ratio w/w) 1:100,000) can be converted into CDs..Essentially 6 bacterial strains (4 bacilli) are known for producing extracellular CGTs. Depending upon the strain and the cultural conditions, 5–430mg of enzyme per 1 of culture filtrate were obtained, and purified up to 140fold (overall yields 10–78%). Because of the different assay methods the CGTs of the various bacterial sources cannot be compared at present. It cannot be decided, therefore, which enzyme is the most suited for the production of CDs on a technical scale..The history of .cyclodextrin glycosyltransferase -research is a very strange one for an enzymologist by several reasons: a) For 70 years only one organism (Bacillus macerans) has been known for producing this type of enzyme. b) Quantitative investigations of the chemistry of the cyclodextrin glycosyltransferases (1,4-a-D-glucan:[1,4-a-D-glucopyranosyl] transferases (cyclizing) (EC 2.4.1.19), CGTs) have been severely handicapped by the lack of a specific assay method. c) As indicated by more than 600 publications and patents (1) the chemists have been fascinated by the clathrate-forming properties of the characteristic cyclic transfer products. In spite of the fact that the CGTs are very interesting enzymes, the investigations of both the enzyme chemistry and the mechanism of the reactions have been neglected..According to D.French, one of the pioneers in CGT-research, “the Schardinger dextrins could be manufactured on a very large scale, if there were a suitable market for them”(2). Up to now, the cyclodextrins (CDs) have been much too expensive for application on a technical scale. Production of CDs of low costs depends upon both an easily available CGT of wellknown characteristics and economic methods for manufacturing the cyclic compounds.
|
| 9 |
A Photometric Test for the Cyclisation Activity of Cyclodextrin-Glycosyltransferases |
J.-P. Landert,E. Flaschel,A. Renken |
|
Abstract
A quick and reliable test has been developed to measure the cyclisation activity of cyclodextrin-glycosyltransferases (CGT). Since the reproducibility depends mostly on the nature of the substrate, maltotriose has been employed. The cyclodextrins (CD) formed are measured directly in situ by complexation with methyl orange and by recording the change of absorbance photometrically. The test has successfully been used with CGT from . M5 al and CGT from alkalophilic ..
|
| 10 |
Action of CGT on Beta Limit Dextrin of Amylopectin |
Rainer Siebert |
|
Abstract
The action of CGT from Klebsiella pneumoniae M 5 al on beta limit dextrin from amylopectin was investigated. It was shown that CGT is shortening the longer B-chains of the substrate under formation of products of low molecular weight.
|
| 11 |
Absorption and Metabolism of β-Cyclodextrin by Rats |
Andrea Gerlóczy,Anna Fónagy,József Szejtli |
|
Abstract
The oxygen consumption of small intestinal slices of rat was measured in Warburg apparatus using glucose, maltose, starch and beta-cyclodextrin as substrates. The oxygen consumption was increased in case of glucose, maltose and starch, while beta-cyclodextrin did not produce any change.
|
| 12 |
Toxicity Studies of Beta-Cyclodextrin |
Vera Gergely,G. Sebestyén,S. Virág |
|
Abstract
The acute oral and parenteral LD-50 of beta-cyclodextrin was established on rats, mice and dogs..The long term toxicity studies were performed on rats and dogs following the two weeks dose finding studies given the test substance by oral route. All of the animals were autopsied and the tissue samples were examined histopathologically in both experiments..Investigation of the effect of beta-cyclodextrin on hepatic drug metabolizing enzyme system of rats did not show any alteration in the activity..According to our results the beta-cyclodextrin given orally to rats and dogs did not cause any side effect during the long term toxicity studies.
|
| 13 |
Absorption and Elimination of Cyclodextrin Derivatives by Rabbits and Rats |
P. Szabó,T. Ferenczy,J. Serfőző,J. Szejtli,A. Lipták |
|
Abstract
The intestinal absorption, digestibility by the colon bacterial flora and urinary elimination of the β-cyclodextrin and its methylated derivatives were studied. The in vitro absorption of the methylated derivatives of cyclodextrin proved to be slow, and could not be inhibited by phloretin. The absorption is concentration dependent, and shows no saturation limit. The results point to a passive transport mechanism. The β-cyclodextrin and its methylated derivative could be digested by a culture of colonic symbionts. The results render quite probable that these compounds may be converted into glucose by the colon bacteria. Following oral administration the urinary elimination was rather low, while following the intramuscular injection the heptakis(2,6-di-0-methyl)-β -cyclodextrin was excreted from the organism quantitatively in 24 hours. The plasma concentration of intravenously injected heptekis-(2,6-di-0-methyl)-β -cyclodextrin decreased abruptly in 1–2 hours, and after 6 hours, it could be detected in blood plasma only in traces.
|
| 14 |
Renal Effects of Parenterally Administered Methylated Cyclodextrins on Rabbits |
J. Serfőző,P. Szabó,T. Ferenczy,A. Tóth-Jakab |
|
Abstract
The renal effects of a 12 days intramuscular treatment with 50 mg/kg/day doses of β-CD, heptakis-monomethyl-β-CD /= MM-β-CD/, heptakis-dimethyl-β-CD /DM-β-CD/ and heptakis-trimethyl-β-CD /= TM- β-CD/ were studied on rabbits, with emphasis on the glomerular circulation of the nephron, and in the ultrastructural changes of the epithelial cells of the proximal tubule..At this relatively high dosis MM- β-CD and TM-β-CD caused an increased necrosis while the effect of β-CD and DM-β-CD were more moderate..MM- β-CD and TM- β-CD reduce the blood supply of the nephron, the concomitant hypoxia increases the lysosomal activity in the epithel cells. This state leads to the development of progrediated necrosis. β-CD and DM- β -CD increase the blood supply of the nephron. In this case the development of necrosis and activation of lysosomal system are caused by the recirculation of these substances connected with their enhanced reabsorption.
|
| 15 |
The Purification and Properties of Cyclodextrin Glycosyltransferase (CGT-ase) of Bacillus Macerans |
G. Seres,E. László |
|
Abstract
The CGT-ase was isolated as an extracellular enzyme from filtrates of three day aged B. macerans cultures. The CGT-ase content of filtrate was purified about 250-fold with affinity chromatography and subsequent gel filtration on Sephacryl-S-200 medium. The resulting enzymatically active fractions were pooled and identified as pure CGT-ase, demonstrated by agarose IEF and ion exchange chromatography techniques..The purified CGT-ase had a molecular weight of 78 K and consisted of a single polypeptide chain established with standard gel filtration procedure on Seeharose CL-6B according to Ansari and had an isoelectric point of 4,5. The purified enzyme was stable at pH 6,0 and lost its activity at 60 °C after a 30 min incubation. The activity and temperature optima were pH 5,6 and 45 °C respectively..The main reaction products of CGT-ase action on amylose were α -and β-cyclodextrins, produced in a consecutive reaction pattern..Studying the IEP patterns of fermentation filtrates it was concluded that CGT-ase activity synthetised by B. macerans is primarily located in the intracellular space and becames extracellular after autolysis of bacterial cells only..In the fermentation broth another amylolytic factor was found which was synthetised mainly at earlier stage e.g. at the proliferation of cells. This new enzyme was also partially purified.
|
| 16 |
A Rapid Method for Determination of CGT-ase Activity |
Zs. Péterfi,G. Seres |
|
Abstract
The known methods for determination of CGT-ase activity are either nonspecific e.g. dextrinizing assay according to KITAHATA et al., or highly subjective e.g. microscopic test reported by TILDEN et al.; moreover they are rather time consuming, as e.g. the glycosyltransferase activity of THOMA et al..The proposed new method is free of these disadvantages. The CGT-ase action is irreversible under the applied reaction conditions. The assay based on the phenomena that CGT-ase splits the alfa-CD content of a reaction mixture and to the newly formed maltohexaose chain covalently bonds one molecule p-nitrophenyl-beta-D-gluco-pyranoside (PNFG). Simultaneously the resulting maltoheptaose-PNFG glycoside is hydrolysed to maltose by hog pancreatic alfa-amylase content of the reaction mixture. The amount of maltose — proportional to the CGT-ase activity — was measured as reducing sugar with common DNS method..The optimised reaction conditions, the CD catalysed hydrolysis of PNFG, the rates of glycosyltransferase coupling reactions with α-CD and PNFG, and K. values were estimated..To demonstrate that this method is insensitive against common alfa-amylases of fermentation broth, the assay was accomplished with samples containing amylases of B.subtilis and hog pancreas. No significant effect was observed, i.e. under the applied circumstances the hydrolitic alfa-amylases do not split the α-CD ring.
|
| 17 |
Enzymatic Investigations with Cyclodextrins |
I. Jodál |
|
Abstract
It is known that the methylated analogues of β-cyclodextrin dissolve in cold water 10–20 times better than β-cyclodextrin itself and have good complex-forming property..It has been investigated how these cyclodextrin derivatives influence the activity of some enzymes..The results of the experiments with lipase indicate that the rate of glyceride-hydrolysis is higher in the aqueous solution of dimethyl-β-cyclodextrin (10 %) than in the presence of the bile as a natural emulgeator..The activity of the alkaline phosphatase rises both in the presence of β-cyclodextrin and dimethyl-β-cyclodextrin..In the case of α-amylase (from Aspergillus oryzae) the in-hibition of the activity by dimethyl-β-cyclodextrin is similar as that of β-cyclodextrin.
|
|
|
|Archiver|手机版|小黑屋|
派博传思国际
( 京公网安备110108008328)
GMT+8, 2025-11-11 08:25
发表于 2025-3-21 19:18:27
