Action Pattern of Bacillus SP. No. 7-M Chitosanase on Partially N-Acetylated Chitosan

Izume, Masato; Nagae, Shinichi; Kawagishi, Hirokazu; Mitsutomi, Masaru; Ohtakara, Akira

doi:10.1007/978-94-011-5942-5_39

Cited by 22 publications

(24 citation statements)

References 9 publications

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“…The general approach of using an activation energy to account for different sequences interacting with the subsites of the enzyme could also be explored for other types of enzymes working on co-polymeric substrates. Alginate M-and G-lyase depolymerizing alginates (22)(23)(24), p-D-mannanase hydrolysing galactomannan (25), and chitinase/chitosanase depolymerizing chitosan (26) are all examples in this respect.…”

Section: Discussionmentioning

confidence: 99%

Sequence specificities for lysozyme depolymerization of partially N-acetylated chitosans

Stokke¹,

Vårum²,

Holme³

et al. 1995

Can. J. Chem.

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The influence of sugar residue sequence in partially N-acetylated chitosans on relative hydrolysis rate catabzed by lysozyme was studied. The relative rates were modelled assuming an Arrhenius-type relation for the relative rate constants. The apparent activation energy was assumed to consist of additive contributions from GlcN or GlcNAc residues within the polymer chain interacting with sites A-F of the active cleft of lysozyme. This model accounted well for the relative hydrolysis rates reported for well-defined oligomers. Calculated and experimental data for the dependence of the initial relative hydrolysis rates on fraction of acetylated units, FA, showed an F~~.~ dependence. A fully water-soluble highly N-acetylated chitosan with FA = 0.68 was depolymerized using lysozyme for further testing of the model. Analyses of the I3c nuclear magnetic resonance spectra of the diad sequences at the new reducing and nonreducing ends formed by lysozyme showed that this enzymatic depolymerization was dominated by chitosan sequences presenting GlcNAc residues to sites C, D, and E of the active cleft. In contrast, there was no selectivity between GlcNAc and GlcN residues interacting with site F. These selectivities were confirmed by the calculated contributions to the apparent activation energy of these sites. The experimentally determined depletion in the diad and triad frequencies of GlcNAc during the course of lysozyme hydrolysis was in good agreement with the model calculations.Key words: lysozyme, chitosan, chitin, sequence specificity, subsite model.Resume : On a CtudiC l'influence de la sCquence des rtsidus de sucre, dans des chitosanes partiellement N-acCtylCs, sur le vitesses relatives d'hydrolyse par le lysozyme. On a fait un modkle des vitesses relatives en supposant qu'on peut leur appliquer une relation du type d'Arrhenius. On a supposC que 1'Cnergie d'activation apparente est formie de contributions additives des rCsidus GlcN ou GlcNAc prksents dans la chai'ne de polymkre avec les sites A 2i F de la cavitC du lysozyme. Ce modkle a permis d'expliquer les vitesses d'hydrolyse relatives rapportCes pour des oligomkres bien dCfinis. Les donnCes calculCes et expCrimentales concernant la dtpendance des vitesses d'hydrolyse relatives initiales sur la fraction d'unitts acCtylCes, FA, prtsentent une dtpendance Dans le but de vCrifier plus a fond le modble et utilisant le lysozyme, on a dCpolymCrisC un chitosane N-acCtylC, complktement soluble dans l'eau et de FA = 0,68. Des analyses par de la rCsonance magnttique nuclCaire I3c des sequences de diades aux extrtmitCs rkductrices et non rtductrices formCes par le lysozyme ont montrC que cette dCpolymCrisation enzymatique est dominCe par des sCquences de chitosane prksentant des rtsidus GlcNAc aux sites C, D et E de la cavitt active. Par opposition, aucune sClectivitC a pu Etre observCe entre les rCsidus GlcNAc et GlcN qui interagissent avec le site F. On a confirm6 ces sClectivitCs par les contributions calculCes a I'Cnergie apparente d'activation de ces sites. ...

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Section: Discussionmentioning

confidence: 99%

Sequence specificities for lysozyme depolymerization of partially N-acetylated chitosans

Stokke¹,

Vårum²,

Holme³

et al. 1995

Can. J. Chem.

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“…6) Suc-Chi was initially developed as wound dressing materials, 7) it is currently also applied as cosmetic materials (Moistˆne liquid ). 8) New wound dressings composed of Suc-Chi and gelatin were also developed. 9) In addition, water-soluble chitin and chitosan including Suc-Chi were applied for a patent as a treatment of arthritis in Japan.…”

Section: Introductionmentioning

confidence: 99%

Preparation of <i>N</i>-Succinyl-chitosan and Their Physical-Chemical Properties as a Novel Excipient

Yan

Chen

et al. 2006

YAKUGAKU ZASSHI

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The aim of this work is to prepare N-succinyl-chitosan (Suc-Chi) and measure physical-chemical properties for Suc-Chi as excipients. Suc-Chi were prepared via ring-opening reactions with succinic anhydride in Dimethyl Sulfoxide system. The physical-chemical properties of Suc-Chi, such as the degree of substitution (DS), solubility, isoelectric point (pI), glass transition temperature (Tg), partition coe‹cient (P app ) and zata potential were detected respectively in order to evaluate their possibility as drug carriers. We obtained Suc-Chi DAC-90 (DS＝0.33) and the data of physicalchemical properties for the product. The knowledges of physical-chemical properties for Suc-Chi are valuable for basic or applied purposes in biomedical and pharmaceutical sciences stabilization.

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“…Muitas blendas formadas pela combinação de biopolímeros, têm grande importância na área de biomateriais, sendo que é possível juntar as propriedades individuais de cada material em um só, além da possibilidade de melhorar ou controlar as suas propriedades mecânicas e biológicas através da interação entre as suas estruturas quí-micas diferentes. Recentemente, membranas e hidrogéis provenientes da mistura de colágeno e quitosana foram investigados pelas suas aplicações potenciais no campo dos biomateriais 9,10 . Já foi demostrado que as interações entre o colágeno e a quitosana dependem da organização estrutural do colágeno e da quantidade e distribuição de cargas ao longo das cadeias dos dois polímeros 11 .…”

Section: Introductionunclassified

Obtenção e caracterização de blendas colágeno-quitosana

Tonhi¹,

Plepis²

2002

Quím. Nova

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Recebido em 15/8/01; aceito em 19/2/02 PREPARATION AND CHARACTERIZATION OF COLLAGEN-CHITOSAN BLENDS. Biodegradable polymer blends were obtained using collagen and chitosan. Membranes of collagen and chitosan in different proportions (3:1, 1:1 and 1:3) were prepared by mixing their acetate solutions (pH 3.5) at room temperature. The blends were characterized by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier Transform infrared (FTIR) spectroscopy, specific viscosity, water absorption and stress-strain assays. The results showed that chitosan did not interfere in the structural arrangement of the collagen triple helix and the properties of the blends can be controlled by varing the proportion of the collagen and the chitosan.Keywords: blends; collagen; chitosan. INTRODUÇÃOO colágeno é uma proteína fibrosa presente na pele, tendões, ossos, dentes, vasos sangüíneos, intestinos e cartilagens, correspondendo a 30% da proteína total e a 6% em peso do corpo humano.A quitosana é um copolímero constituído de b-(1-4)-2-amino-2-deoxi-D-glicopiranose e b-(1-4)-2-acetamida-2-deoxi-D-glicopiranose, proveniente da reação de desacetilação da quitina, o segundo polissacarídeo mais abundante na natureza.O colágeno e a quitosana têm sido bastante utilizados na medicina, odontologia e farmacologia como biomateriais, pois são polímeros biocompatíveis, atóxicos e biodegradáveis, além de possuírem inú-meras propriedades biológicas [1][2][3][4][5][6] . As blendas poliméricas constituem-se na mistura de pelo menos dois polímeros ou copolímeros sem que haja qualquer reação quími-ca entre eles 7 . O interesse nesta área deve-se às crescentes aplicações práticas destes novos materiais e os principais estudos são voltados para a melhoria de suas propriedades físicas, físico-químicas e de processamento destes materiais, comparadas às propriedades dos polímeros puros 8 . Muitas blendas formadas pela combinação de biopolímeros, têm grande importância na área de biomateriais, sendo que é possível juntar as propriedades individuais de cada material em um só, além da possibilidade de melhorar ou controlar as suas propriedades mecânicas e biológicas através da interação entre as suas estruturas quí-micas diferentes. Recentemente, membranas e hidrogéis provenientes da mistura de colágeno e quitosana foram investigados pelas suas aplicações potenciais no campo dos biomateriais 9,10 . Já foi demostrado que as interações entre o colágeno e a quitosana dependem da organização estrutural do colágeno e da quantidade e distribuição de cargas ao longo das cadeias dos dois polímeros 11 . Estas propriedades estão diretamente relacionadas com o pH do meio, que é uma propriedade de fundamental importância para o estudo da interação entre eles em solução.Este trabalho teve por objetivos obter blendas colágeno-quitosana em diferentes proporções (3:1, 1:1 e 1:3) em pH 3,5, estudar a interação entre estes dois biopolímeros tanto na forma de membranas como em solução e avaliar suas propriedades físico-químicas. PARTE EXPERIMENTAL C...

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Action Pattern of Bacillus SP. No. 7-M Chitosanase on Partially N-Acetylated Chitosan

Cited by 22 publications

References 9 publications

Sequence specificities for lysozyme depolymerization of partially N-acetylated chitosans

Sequence specificities for lysozyme depolymerization of partially N-acetylated chitosans

Preparation of <i>N</i>-Succinyl-chitosan and Their Physical-Chemical Properties as a Novel Excipient

Obtenção e caracterização de blendas colágeno-quitosana

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