SEARCH · PubMed Health

Results for “chitinase”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources

PubMed1992

The complete amino acid sequence of yam (Dioscorea japonica) chitinase. A newly identified acidic class I chitinase.

The complete amino acid sequence of acidic chitinase from yam (Dioscorea japonica) aerial tubers was determined. The protein is composed of a single polypeptide chain of 250 amino acid residues and has a calculated molecular mass of 27,890 Da. There is an NH2-terminal domain, a hinge region, and a main structure, typical for class I chitinases (Shinshi, H., Neuhaus, J.-M., Ryals, J., and Meins, F., Jr. (1990) Plant Mol. Biol. 14, 357-368). We have obtained the first evidence for an acidic class I chitinase. Comparison with sequences of other class I chitinases revealed approximately 40% sequence similarity, a value lower than that for other class I chitinases (70-80%). We assume that there is a local conformational change in the molecule; cysteine residues that probably form disulfide bonds are completely conserved, with the exception of Cys-178. The difference in structure between this chitinase and other basic class I chitinases suggests that acidic and basic isoforms should be grouped into subclasses; this protein is an ethylene- or a pathogen-independent chitinase produced by a gene that is inherent in the tuber.

Amino Acid Sequence↗

PubMed1992

Primary structure of a chitinase-encoding gene (chi1) from the filamentous fungus Aphanocladium album: similarity to bacterial chitinases.

Chitinase 1 (Chi1) is the major extracellular chitinase from the hyperparasitic fungus, Aphanocladium album. We determined the complete sequence of the chromosomal and cDNA copies of the structural gene (chi1) coding for Chi1. The coding region is interrupted by three short introns (55, 53 and 49 bp long). Chi1 is 423 aa long and begins with a stretch of 34 aa not found in the mature protein. The Chi1 sequence presents overall similarities with bacterial chitinases from Serratia marcescens and Bacillus circulans. Compared with other chitinases, A. album Chi1 has only two short similarity regions (12 and 8 aa long), which are also found in bacterial, yeast and some plant chitinases.

Amino Acid Sequence↗

PubMed1992

Purification of two chitinases from Rhizopus oligosporus and isolation and sequencing of the encoding genes.

Two chitinases were purified from Rhizopus oligosporus, a filamentous fungus belonging to the class Zygomycetes, and designated chitinase I and chitinase II. Their N-terminal amino acid sequences were determined, and two synthetic oligonucleotide probes corresponding to these amino acid sequences were synthesized. Southern blot analyses of the total genomic DNA from R. oligosporus with these oligonucleotides as probes indicated that one of the two genes encoding these two chitinases was contained in a 2.9-kb EcoRI fragment and in a 3.6-kb HindIII fragment and that the other one was contained in a 2.9-kb EcoRI fragment and in a 11.5-kb HindIII fragment. Two DNA fragments were isolated from the phage bank of R. oligosporus genomic DNA with the synthetic oligonucleotides as probes. The restriction enzyme analyses of these fragments coincided with the Southern blot analyses described above and the amino acid sequences deduced from their nucleotide sequences contained those identical to the determined N-terminal amino acid sequences of the purified chitinases, indicating that each of these fragments contained a gene encoding chitinase (designated chi 1 and chi 2, encoding chitinase I and II, respectively). The deduced amino acid sequences of these two genes had domain structures similar to that of the published sequence of chitinase of Saccharomyces cerevisiae, except that they had an additional C-terminal domain. Furthermore, there were significant differences between the molecular weights experimentally determined with the two purified enzymes and those deduced from the nucleotide sequences for both genes. Analysis of the N- and C-terminal amino acid sequences of both chitinases and comparison of them with the amino acid sequences deduced from the nucleotide sequences revealed posttranslational processing not only at the N-terminal signal sequences but also at the C-terminal domains. It is concluded that these chitinases are synthesized with pre- and prosequences in addition to the mature enzyme sequences and that the prosequences are located at the C terminal.

Amino Acid Sequence↗

PubMed1992

Cloning and characterization of a pathogen-induced chitinase in Brassica napus.

A chitinase cDNA clone from rapeseed (Brassica napus L. ssp. oleifera) was isolated. The cDNA clone, ChB4, represents a previously purified and characterized basic chitinase isozyme. The longest open reading frame in ChB4 encodes a polypeptide of 268 amino acids. This polypeptide consists of a 24 amino acid N-terminal signal peptide, a cysteine-rich domain and a catalytic domain. The primary structure of the mature ChB4 shows a low degree of identity with class I and II chitinases, 43-48% and 35%, respectively. In contrast, ChB4 shows 62% identity to a basic sugar-beet chitinase and 63% identity to an acidic chitinase from bean. The expression of chitinase messenger RNA (mRNA) in response to infection with Phoma lingam (Tode ex. Fr.) Desm. was examined by northern hybridization and scintilation counting. A differential induction was seen between resistant and susceptible cultivars where 3-fold higher chitinase transcript levels were estimated one day after inoculation in resistant as compared to susceptible cultivar. This difference diminished eight days after inoculation. Southern hybridization analysis indicates that the chitinase is encoded by a small family of genes.

Amino Acid Sequence↗

PubMed1992

Regulated inactivation of homologous gene expression in transgenic Nicotiana sylvestris plants containing a defense-related tobacco chitinase gene.

The class I chitinases are vacuolar proteins implicated in the defense of plants against pathogens. Leaves of transgenic Nicotiana sylvestris plants homozygous for a chimeric tobacco (Nicotiana tabacum) chitinase gene with Cauliflower Mosaic Virus (CaMV) 35S RNA expression signals usually accumulate high levels of chitinase relative to comparable leaves of non-transformed plants. Unexpectedly, some transgenic plants accumulated lower levels of chitinase than nontransformed plants. We call this phenomenon silencing. The incidence of silencing depends on the early rearing conditions of the plants. When grown to maturity in a greenhouse, approximately 25% of plants raised as seedlings in closed culture vessels were of the silent type; none of the plants raised from seed in a greenhouse showed this phenotype. Silencing is also developmentally regulated. Plants showed three patterns of chitinase expression: uniformly high levels of expression in different leaves, uniformly low levels of expression in different leaves, and position-dependent silencing in which expression was uniform within individual leaves but varied in different leaves on the same plant. Heritability of the silent phenotype was examined in plants homozygous for the transgene. Some direct descendants exhibited a high-silent-high sequence of activity phenotypes in successive sexual generations, which cannot be explained by simple Mendelian inheritance. Taken together, the results indicate that silencing results from stable but potentially reversible states of gene expression that are not meiotically transmitted. Gene-specific measurements of chitinase and chitinase mRNA showed that silencing results from co-suppression, i.e. the inactivation of both host and transgene expression in trans. The silent state was not correlated with cytosine methylation of the transgene at the five restriction sites investigated.

Base Sequence↗

PubMed2026

Humanizing acidic mammalian chitinase variants establish lung immune conditioning and control environmentally driven inflammation and fibrosis.

Chitin, a widespread environmental particle constituent, triggers lung inflammation but is degraded by chitinases. In humans, single-nucleotide polymorphisms (SNPs) in CHIA (acidic mammalian chitinase; AMCase) are associated with lung disease, suggesting that chitinase variants influence responses to airborne particles. Here, we edit the mouse Chia1 locus to generate humanized (hChia) mice harboring common human SNPs. Compared with controls expressing disease-protective SNPs, hChia mice lack robust chitinase activity and fail to degrade natural chitin substrates. Lung-resident lymphocytes and macrophages are spontaneously primed and sensitive to inflammatory triggering by environmental chitin. Immune cell infiltration correlates with airway chitin following challenge, and hChia mice exhibit exacerbated inflammatory and fibrotic lung disease. In humans with acute respiratory failure, alveolar hemorrhage coincides with environmentally derived chitin particles that are susceptible to chitinase degradation, attenuating inflammatory cell responses. Thus, environmental chitin and chitinase activity are crucial determinants of lung immune conditioning with potential therapeutic applications.

AMCase↗

PubMed1992

Production of chitinase by enterotoxigenic Aeromonas species isolated from clinical and environmental sources.

Thirty-six isolates of Aeromonas, 13 from children and 23 from the environment were tested for production of chitinase in culture supernatants. Thirty-four isolates of the three species (91% clinical and 96% environmental) produced constitutive chitinase. The environmental isolates elaborated significantly more (p < 0.005) of the enzyme than those from the children. Four of the environmental isolates also produced inducible chitinase. All isolates of Aeromonas were enterotoxic, however, the isolates producing inducible chitinase showed significantly higher enterotoxic activity. This study indicates that there is correlation between production of enterotoxin and chitinase in Aeromonas species.

Aeromonas↗

PubMed1992

The gene for stinging nettle lectin (Urtica dioica agglutinin) encodes both a lectin and a chitinase.

Chitin-binding proteins are present in a wide range of plant species, including both monocots and dicots, even though these plants contain no chitin. To investigate the relationship between in vitro antifungal and insecticidal activities of chitin-binding proteins and their unknown endogenous functions, the stinging nettle lectin (Urtica dioica agglutinin, UDA) cDNA was cloned using a synthetic gene as the probe. The nettle lectin cDNA clone contained an open reading frame encoding 374 amino acids. Analysis of the deduced amino acid sequence revealed a 21-amino acid putative signal sequence and the 86 amino acids encoding the two chitin-binding domains of nettle lectin. These domains were fused to a 19-amino acid "spacer" domain and a 244-amino acid carboxyl extension with partial identity to a chitinase catalytic domain. The authenticity of the cDNA clone was confirmed by deduced amino acid sequence identity with sequence data obtained from tryptic digests, RNA gel blot, and polymerase chain reaction analyses. RNA gel blot analysis also showed the nettle lectin message was present primarily in rhizomes and inflorescence (with immature seeds) but not in leaves or stems. Chitinase enzymatic activity was found when the chitinase-like domain alone or the chitinase-like domain with the chitin-binding domains were expressed in Escherichia coli. This is the first example of a chitin-binding protein with both a duplication of the 43-amino acid chitin-binding domain and a fusion of the chitin-binding domains to a structurally unrelated domain, the chitinase domain.

Amino Acid Sequence↗

PubMed1992

Chemical modification studies of the active centre of Candida albicans chitinase and its inhibition by allosamidin.

Allosamidin, a glycoside antibiotic, is shown to be a strong, competitive inhibitor of semi-purified chitinase from yeast cells of Candida albicans. The inhibitory potency of allosamidin was pH-dependent, with IC50 values of 280 nM at pH 5.0 and 21 nM at pH 7.5. At higher, micromolar, concentrations, allosamidin inactivated this chitinase in a time- and concentration-dependent manner. Kinetic studies of this inactivation provided evidence for the formation of a reversible complex between allosamidin and chitinase, characterized by Kinact = 5 microM, followed by irreversible modification of the enzyme with velocity constant k2 = 4.6 x 10(-3) s-1. Chemical modification studies with the use of group-specific reagents suggested the presence of Glu/Asp carboxyl group(s) at or near the active site, that were important for enzyme activity. The carboxyl-specific reagent, 1-ethyl-3(3-dimethylaminopropyl)-carbodiimide, inactivated the chitinase in a single step process, with apparent second-order rate constant of 0.014 M-1 s-1.

Acetylglucosamine↗

PubMed1976

Chitinase and beta-N-acetylglycosaminidase in the digestive juice of Helix pomatia.

A beta-N-acetylglucosaminidase from Helix pomatia digestive juice was separated and partly purified by gel chromatography. The optimal pH for the degradation of p-nitrophenyl-N-acetyl-beta-D-glucosaminide was 3.4. The molecular weight was around 160 000 and the pI = 4.95. In the same gel chromatography run two chitinase active peaks were also obtained. These chitinase active peaks were also obtained. These chitinases, with molecular weights around 26 000 and 13 000, had somewhat different pH activity curves with optima at 4.2 and 4.3. By isoelectric focusing the first peak with molecular weight around 26 000 was divided in two chitinase active regions with pI at 5.7 and 3.5. The second peak with molecular weight around 13 000 had a pI at 7.3.

Acetylglucosaminidase↗

PubMed1979

The effect of beta-glucuronidase and chitinase on the cell wall of Aspergillus niger and Aspergillus fumigatus.

The effects of beta-glucuronidase and chitinase have been tested on the hydrolysis of the cell walls of the economically important fungi, Aspergillus niger and Aspergillus fumigatus. The extent of wall hydrolysis was measured by assaying for total reducing sugars, N-acetyl sugars and protoplast production. Maximum reducing sugar release was attained after 40 min incubation, both with beta-glucuronidase supplemented with chitinase and beta-glucuronidase alone, whereas N-acetyl sugar release reached a maximum at 80 min incubation. beta-Glucuronidase was effective in releasing protoplasts from both species of Aspergillus. This release was enhanced by adding chitinase to the incubation medium at 0 and 20 min, but with addition at 60, 80 and 100 min increase in protoplast yield was much reduced. The results of re-incubation experiments with chitinase suggest that this enzyme may in some way be inhibited during the later stages of incubation. Pronase used in combination with beta-glucuronidase slightly enhanced protoplast release.

Aspergillus fumigatus↗

PubMedDate not supplied

[Chitinase from Serratia marcescens BKM B-851].

The chitinase biosynthesis was studied during the cultivation of the strain of Serratia marcescens BKM B-851 with a high chitinolytic activity. Under submerged cultivation of bacterial cells on the medium containing demineralized crab shell extracellular chitinase showed maximum activity on the 3rd day. Cells of S. marcescens BKM B-851 synthesized chitinase as an adaptive enzyme. Chitinase obtained from the culture liquid by ammonium sulphate precipitation was then dialyzed and liophylized. It displayed optimum hydrolysis of colloid chitin at pH 7-8 and 50 degrees C and of native chitin at 30 degrees C.

Brachyura↗

PubMedDate not supplied

[Biosynthesis of chitinase by Achromobacter liquefaciens].

Bacterial cultures under study synthesize exocellular chitinase on a medium containing chitin or demineralized crab shells as a source of carbon and nitrogen. Conditions for biosynthesis of chitinase by the cells of Achromobacter liquefaciens 301a were investigated under periodic and continuous conditions of cultivation. The preparation of chitinase isolated from the cultural broth of A. liquefaciens 301a hydrolysed colloid and native chitin at the optimum pH 6.5 and temperature 40degreesC. The terminal products of the reaction are chitobiose and N-acetylglucosamine.

Acetylglucosamine↗

PubMedDate not supplied

[Production of chitinase by Actinomyces kurssanovii and its properties].

Actinomyces kurssanovii, a culture producing large amounts of chitinase and chitobiase, was cultivated on a medium of the following composition (%): demineralized crab shells, 3.0; K2HPO4, 0.5; peptone, 0.2; yeast extract, 0.1; MgSO4-H2O, 0.09. The maximum amount of the enzymes was synthesized after growth in a fermenter of the actinomycete during 48 hours. The highest activity of chitinase is manifested at pH 7.0 and depends on ionic composition of the buffer, being higher in veronal buffer than in phosphate or tris//HC1 buffers. The chitinase and chitobiase of the strain decompose completely colloid chitin and chitin in demineralized crab shells with the formation of N-acetyl-D-glucosamine.

Actinomyces↗

PubMedDate not supplied

[Chitinase of Bacillus thuringiensis].

Strains of Bacillus thuringiensis were shown to hydrolyse various forms of chitin around growing colonies on a solid medium. In conditions of submerged cultivation on a medium containing demineralized crab shells, Bac. thuringiensis var. caucasicus INMI Arm. 837 manifests the chitinolytic activity at the beginning of the stationary growth phase. The activity of chitinase which is of a constitutive nature increases when the bacterium is cultivated at pH 7.2. The maximum rate of hydrolysis of colloid chitin by chitinase prepared from the cultural broth is displayed at pH 8.0 and 60 degrees C.

Bacillus thuringiensis↗

PubMed1990

Action pattern of Aeromonas hydrophila chitinase on partially N-acetylated chitosan.

Oligosaccharides from the digestion of 34% N-acetylated chitosan by Aeromonas hydrophila chitinase were separated by CM-Sephadex C-25 column chromatography. Sugar compositions and the sequences of main oligosaccharides were identified through their N-acetylation, their cleavage with exo-glycosidases, and their degradation with nitrous acid. Hetero-chitooligosaccharides such as GlcN.GlcNAc, GlcN.GlcNAc.GlcNAc, GlcNAc.GlcN.GlcNAc, and GlcNAc.GlcN.GlcNAc.GlcNAc, together with GlcNAc and (GlcNAc)2, were detected. The structure of GlcN.GlcNAc was confirmed by the analysis with proton and carbon NMR spectroscopy. These studies indicate that Aeromonas hydrophila chitinase is more specific toward the N-acetyl-beta-D-glucosaminidic bonds in partially N-acetylated chitosan.

Acetylation↗

PubMed1990

Action pattern of Streptomyces griseus chitinase on partially N-acetylated chitosan.

Oligosaccharides produced during the course of the hydrolysis of 25% N-acetylated chitosan by Streptomyces griseus chitinase were fractionated by CM-Sephadex C-25 and Toyopearl HW-40F column chromatographies. Sugar compositions and sequences of main oligosaccharides were identified by N-acetylation, exo-splitting with beta-GlcNAcase and beta-GlcNase, and nitrous acid degradation. In addition to N-acetylated saccharides, GlcNAc, (GlcNAc)2, and (GlcNAc)3, hetero-chitooligosaccharides such as GlcN.GlcNAc, GlcN.GlcNAc.GlcNAc, GlcN.GlcN.GlcNAc, GlcN.GlcNAc.GlcNAc.GlcNAc, GlcNAc.GlcN.GlcNAc.GlcNAc, GlcN.GlcNAc.GlcN.GlcNAc, and GlcN.GlcN.GlcNAc.GlcNAc were identified. These results indicate that Streptomyces griseus chitinase specifically cleaves the N-acetyl-beta-D-glucosaminidic linkages in partially N-acetylated chitosan.

Acetylation↗

PubMedDate not supplied

[Physiological and biochemical properties of Actinomyces kurssanovii, active producter of chitinase].

Chitinase biosynthesis by Actinomyces kurssonovii 75 was studied under conditions of periodic cultivation in a laboratory fermenter. The activity of components of the chitinolytic complex correlated with the growth phases of the culture. The activity of chitobiase (beta-N-acetylglucoseaminidase) predominated in the cultural broth in the exponential growth phase of the culture; it decreased later by 40-50 per cent, while the activity of chitinase became maximum. The biosynthesis of chitinolytic enzymes by the growing actinomycete was accompanied with a rapid hydrolysis of demineralized crab shells, and a gradual increase in the pH of the medium to 9.0. A chitinolytic preparation obtained from the supernatant of the cultural broth of Act kurssanovii hydrolysed ground chitin by 70-80 per cent during 5 days. Fe2+ and Ca2+ ions increased the activity of the preparation by 25 and 30 per cent respectively; Mn2+ ions decreased the activity by 40 per cent.

Acetylglucosaminidase↗