Chitin solutions and purification of chitin

Austin, Paul R.

doi:10.1016/0076-6879(88)61046-9

Cited by 43 publications

(26 citation statements)

References 6 publications

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“…Some authors believe that chitin is built up of at least 60% of GlcNAc residues [3], although a rigid nomenclature with respect to the degree of N-acetylation (defined as the average number of GlcNAc units per 100 monomers expressed as a percentage, DA) between chitin and chitosan has not been defined [4]. It should be mentioned that both compounds are insoluble in water (pH = 7) and common organic solvents, although they can be dissolved in specific solvents such as hexafluoro-2-propanol, N,N-dimethylacetamide or hexafluoroacetone [5][6][7]. Chitin is, next to cellulose, the second most abundant natural biopolymer.…”

Section: Introductionmentioning

confidence: 99%

Biomedical Activity of Chitin/Chitosan Based Materials—Influence of Physicochemical Properties Apart from Molecular Weight and Degree of N-Acetylation

et al. 2011

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Abstract:The physicochemical nature of chitin and chitosan, which influences the biomedical activity of these compounds, is strongly related to the source of chitin and the conditions of the chitin/chitosan production process. Apart from widely described key factors such as weight-averaged molecular weight (M W ) and degree of N-acetylation (DA), other physicochemical parameters like polydispersity (M W /M N ), crystallinity or the pattern of acetylation (P A ) have to be taken into consideration. From the biological point of view, these parameters affect a very important factor-the solubility of chitin and chitosan in water and organic solvents. The physicochemical properties of chitosan solutions can be controlled by manipulating solution conditions (temperature, pH, ionic strength, concentration, solvent). The degree of substitution of the hydroxyl and the amino groups or the degree of quaternization of the amino groups also influence the mechanical and biological properties of chitosan samples. Finally, a considerable research effort has been directed towards developing safe and efficient chitin/chitosan-based products because many factors, like the size of nanoparticles, can determine the biomedical characteristics of medicinal products. The influence of these factors on the biomedical activity of chitin/chitosan-based products is presented in this report in more detail. OPEN ACCESSPolymers 2011, 3 1876

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Section: Introductionmentioning

confidence: 99%

Biomedical Activity of Chitin/Chitosan Based Materials—Influence of Physicochemical Properties Apart from Molecular Weight and Degree of N-Acetylation

et al. 2011

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“…On the other hand, the activities of ChiA⌬5 were higher than those of ChiA⌬4 when colloidal chitin or chitosan 10B was used as a substrate. It is well known that the acid and alkaline treatments for preparations of the colloidal chitin and chitosan 10B are accompanied by low molecularization and a consequent increase of chitin ends (27,28). Indeed, the viscosity of chitosan 10B was approximately one-third of that of the other chitosans used in our experiments.…”

Section: Discussionmentioning

confidence: 99%

Different Cleavage Specificities of the Dual Catalytic Domains in Chitinase from the Hyperthermophilic Archaeon Thermococcus kodakaraensis KOD1

Tanaka¹,

Fukui²,

Imanaka³

2001

Journal of Biological Chemistry

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The chitinase from the hyperthermophilic archaeon Thermococcus kodakaraensis KOD1, Tk-ChiA, has an interesting multidomain structure containing dual catalytic domains and triple chitin-binding domains. To determine the biochemical properties of each domain, we constructed deletion mutant genes corresponding to the individual catalytic domains and purified the recombinant proteins. A synergistic effect was observed when chitin was degraded in the presence of both catalytic domains, suggesting different cleavage specificity of these domains. Analyses of degradation products from N-acetyl-chitooligosaccharides and their chromogenic derivatives with thin layer chromatography indicated that the N-terminal catalytic domain mainly hydrolyzed the second glycosidic bond from the nonreducing end of the oligomers, whereas the C-terminal domain randomly hydrolyzed glycosidic bonds other than the first bond from the nonreducing end. Both catalytic domains formed diacetyl-chitobiose as a major end product and possessed transglycosylation activity. Further analysis of degradation products from colloidal chitin with high performance liquid chromatography showed that the N-terminal catalytic domain exclusively liberated diacetyl-chitobiose, whereas reactions with the C-terminal domain led to N-acetyl-chitooligosaccharides of various lengths. These results demonstrated that the N-terminal and C-terminal catalytic domains functioned as exo-and endochitinases, respectively. The biochemical results provide a physiological explanation for the presence of two catalytic domains with different specificity and suggest a cooperative function between the two on a single polypeptide in the degradation of chitin.

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“…Chitin samples contain a high content of GlcNAc units; hence, they are insoluble in water and common organic solvents. On the other hand, they dissolve only in solvents such as N,Ndimethylacetamide, hexafluoroacetone or hexafluoro-2-propanol (Pillai et al, 2009;Austin, 1988;Kurita, 2001). When the degree of N-acetylation (defined as the average number of N-acetyl-D-glucosamine units per 100 monomers expressed as a percentage) is less than 50%, chitin becomes soluble in aqueous acidic solutions (pH < 6.0) and is called chitosan (Pillai et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

Influence of the Chemical Structure and Physicochemical Properties of Chitin- and Chitosan-Based Materials on Their Biomedical Activity

Kumirska¹,

Weinhold²,

Czerwicka³

et al. 2011

Biomedical Engineering, Trends in Materials Science

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Chitin solutions and purification of chitin

Cited by 43 publications

References 6 publications

Biomedical Activity of Chitin/Chitosan Based Materials—Influence of Physicochemical Properties Apart from Molecular Weight and Degree of N-Acetylation

Biomedical Activity of Chitin/Chitosan Based Materials—Influence of Physicochemical Properties Apart from Molecular Weight and Degree of N-Acetylation

Different Cleavage Specificities of the Dual Catalytic Domains in Chitinase from the Hyperthermophilic Archaeon Thermococcus kodakaraensis KOD1

Influence of the Chemical Structure and Physicochemical Properties of Chitin- and Chitosan-Based Materials on Their Biomedical Activity

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