Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.15 (pectinase)
 2,440 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A system was developed for the rapid characterization of microbial pectic enzyme complexes and then tested on Erwinia chrysanthemi and Sclerotium rolfsii. Pectic enzymes in minute samples of crude culture filtrates were resolved by ultrathin-layer polyacrylamide gel isoelectric focusing and sodium dodecyl sulfate-polyacrylamide gel electrophoresis and then assayed with an ultrathin pectate-agarose overlay stained with ruthenium red. The simple procedure can be completed within 30 min after isoelectric focusing, can detect extremely low levels of pectate lyase (6.4 x 10 mumol of product per min), and is sufficiently sensitive to determine the pectate lyase isozyme profile of a single bacterial colony with a diameter of 4 mm. Pectate lyases and polygalacturonases can be distinguished by altering buffer conditions in the overlays. The assay system revealed additional isozymes not resolved by classical techniques and generally corroborated the previously published isoelectric points and molecular weights of the pectate lyase isozymes and exo-poly-alpha-d-galacturonosidase produced by E. chrysanthemi and the endopolygalacturonase and exopolygalacturonase produced by S. rolfsii.
Appl Environ Microbiol 1985 Sep
PMID:Activity stain for rapid characterization of pectic enzymes in isoelectric focusing and sodium dodecyl sulfate-polyacrylamide gels. 1634 81

Comparative analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of culture supernatants of a virulent Pseudomonas solanacearum strain and of a spontaneous avirulent mutant derived from it was performed. The results show that the levels of two major polypeptides with molecular masses of 43 and 25 kilodaltons (kDa) were markedly reduced in the spent culture medium of the avirulent mutant. In addition, enzyme assays showed that the level of carboxymethyl cellulase (endoglucanase) activity in the culture supernatants of the avirulent mutant was reduced over 25-fold, whereas polygalacturonase activities in both strains were nearly identical. Purification of the endoglucanase from the spent culture medium of the virulent P. solanacearum strain by adsorption to phosphocellulose, salt elution, and gel-filtration chromatography yielded a >95% pure preparation of the 43-kDa polypeptide. The kinetic and enzymatic properties of the purified endoglucanase were subsequently analyzed. Antibody prepared against the purified 43-kDa endoglucanase was used to demonstrate its production by several strains of P. solanacearum races 1 and 2.
Appl Environ Microbiol 1987 Sep
PMID:Purification and Characterization of an Endoglucanase from Pseudomonas solanacearum. 1634 43

The expression of a gene encoding the cell wall-degrading enzyme polygalacturonase [poly(1,4-alpha-D-galacturonide) glucanohydrolase, EC 3.2.1.15] was characterized during tomato fruit ripening. Polygalacturonase was purified from ripe tomato fruit and used to produce highly specific antiserum. Immunoblot analyses detected a 45- and a 46-kDa protein in ripe fruit but immunoprecipitation of in vitro translation products of mRNA from ripe tomato fruit yielded a single 54-kDa polypeptide, suggesting post-translational processing. A plasmid cDNA library was prepared from poly(A)(+) RNA isolated from ripe tomato fruit. The cDNA library was inserted into a lambda-based expression vector, and polygalacturonase cDNA clones were identified by immunological screening. Hybrid-select translation experiments indicated that the cDNAs encode a 54-kDa in vitro translation product that is specifically immunoprecipitated with polygalacturonase antiserum. RNA-blot analysis indicated that the 1.9-kilobase polygalacturonase mRNA was virtually absent from immature-green fruit, accumulated steadily during the ripening process, and was at its highest level in red-ripe fruit. There was at least a 2000-fold increase in the level of polygalacturonase mRNA between immature-green and red-ripe tomato fruit. These studies show that the levels of polygalacturonase mRNA are developmentally regulated during tomato fruit ripening.
Proc Natl Acad Sci U S A 1986 Sep
PMID:Molecular cloning of tomato fruit polygalacturonase: Analysis of polygalacturonase mRNA levels during ripening. 1659 52

Our previous work (E. Shedletzky, M. Shmuel, D.P. Delmer, D.T.A. Lamport [1990] Plant Physiol 94:980-987) showed that suspension-cultured tomato cells adapted to growth on the cellulose synthesis inhibitor 2,6-dichlorobenzonitrile (DCB) have a markedly altered cell wall composition, most notably a markedly reduced level of the cellulose-xyloglucan network. This study compares the adaptation to DCB of two cell lines from dicots (tomato [Lycopersicon esculentum] and tobacco [Nicotiana tabacum]) and a Graminaceous monocot (barley [Hordeum bulbosum] endosperm). The difference in wall structures between the dicots and the monocot is reflected in the very different types of wall modifications induced by growth on DCB. The dicots, having reduced levels of cellulose and xyloglucan, possess walls the major integrity of which is provided by Ca(2+)-bridged pectates because protoplasts can be prepared from these cells simply by treatment with divalent cation chelator and a purified endopolygalacturonase. The tensile strength of these walls is considerably less than walls from nonadapted cells, but wall porosity is not altered. In contrast, walls from adapted barley cells contain very little pectic material and normal to elevated levels of noncellulosic polysaccharides compared with walls from nonadapted cells. Surprisingly, they have tensile strengths higher than their nonadapted counterpart, although cellulose levels are reduced by 70%. Evidence is presented that these walls obtain their additional strength by an altered pattern of cross-linking of polymers involving phenolic components. Such cross-linking may also explain the observation that the porosity of these walls is also considerably reduced. Cells of adapted lines of both the dicots and barley are resistant to plasmolysis, suggesting that they possess very strong connections between the wall and the plasma membrane.
Plant Physiol 1992 Sep
PMID:Cell Wall Structure in Cells Adapted to Growth on the Cellulose-Synthesis Inhibitor 2,6-Dichlorobenzonitrile : A Comparison between Two Dicotyledonous Plants and a Graminaceous Monocot. 1665 33

Cell wall changes leading to the formation of the separation layer during abscission of unifoliate (Phaseolus vulgaris) leaves are reviewed. Based on evidence from explants and intact plants, dissolution of pectic substances between cells of adjacent tissue regions (petiole and pulvinus) is necessary and may be sufficient to form the separation layer. Initially, the abscission zone is not structurally weak. The decline in break strength accompanying formation of the separation layer correlates with the appearance of pectinase activity. Pectinase activity is not detectable in freshly harvested explants but increases to about 0.09 mug per abscission zone at the time of 50% separation. At the same time, water extractable pectin fractions increase with a corresponding decline in the pectin fraction extractable with dilute acid. Separation is aided by internal shear forces generated by differential growth and hydrostatic pressure or both.
Plant Physiol 1968 Sep
PMID:Cell wall dissolution and enzyme secretion during leaf abscission. 1665 18

Oat (Avena sativa L.) aleurone layer cells (spheroplasts) were isolated by maceration of the aleurone layer with a mixture of commercially available cellulase and pectinase. About 20% of the cells present in intact layers were released as spheroplasts and 79 +/- 9% of the spheroplast population was viable as judged by methylene blue staining. The spheroplasts became disorganized in solutions containing less than 0.4 md-mannitol. When the spheroplasts were incubated for 48 hours, total activities of acid p-nitrophenyl phosphatase and acid proteinase increased and protein levels decreased. These changes were not effected by gibberellin A(3). Isolated aleurone layers incubated under the same conditions as the spheroplasts showed reduced responses to gibberellin A(3). It is concluded that the necessary presence of an osmoticum limits the value of spheroplasts as a system for studying the mechanism of action of gibberellin A(3) in the aleurone cell.
Plant Physiol 1977 Sep
PMID:Responses of enzymically isolated aleurone cells of oat to gibberellin a(3). 1666 Jan 14

A large pectic polysaccharide, called rhamnogalacturonan I, that is solubilized by a fungal endo-alpha-1,4-polygalacturonase from the purified walls of suspension-cultured sycamore cells possesses proteinase inhibitor-inducing activity similar to that of the proteinase inhibitor-inducing factor, a pectic-like oligosaccharide fraction isolated from tomato leaves. This suggests that the proteinase inhibitor-inducing activity resides in particular polysaccharide fragments which can be released when plant cell walls are exposed to appropriate enzyme degradation as a result of either wounding or pest attack.
Plant Physiol 1981 Sep
PMID:A sycamore cell wall polysaccharide and a chemically related tomato leaf polysaccharide possess similar proteinase inhibitor-inducing activities. 1666 67

Aluminum chloride induced mesophyll protoplasts of oat (Avena sativa) to produce an extracellular polysaccharide (EPS). EPS induced by AlCl(3) appeared identical to that produced in response to the phytotoxin victorin (JD Walton, ED Earle [1985] Planta 165: 407-415). Al ions at 1 millimolar were toxic to protoplasts, but maximum EPS production occurred at a sublethal concentration of 200 micromolar, assayed at pH 6.0. As measured by incorporation of [(14)C]glucose, AlCl(3) stimulated EPS production 10- to 15- fold. Pretreatment of protoplasts with cycloheximide prevented EPS production but not cell death in response to AlCl(3), indicating that protein synthesis was necessary for EPS production but not for the phytotoxicity of Al ions. The trivalent salts of Y, Yb, Gd, and In also induced EPS production but those of Sc, Fe, Ga, Cr, and La did not. Mesophyll protoplasts from an acid-soil tolerant oat cultivar, Coker 83-23, produced less EPS in response to AlCl(3) than the acid-soil sensitive cultivar Fla 501. EPS was also produced by wheat (Triticum aestivum) and barley (Hordeum vulgare) protoplasts in response to AlCl(3). An Al-tolerant cultivar of wheat, Atlas, produced less EPS than an Al-sensitive cultivar, Scout, but an Al-tolerant cultivar of barley, Dayton, produced more than the Al-sensitive cultivar Kearney. Therefore, production of EPS by protoplasts in response to Al ions did not appear to be related to Al ion tolerance at the level of whole plants. EPS fluoresced in the presence of Calcofluor and Sirofluor and was degraded by purified laminarinase [(1-->3)beta-d-glucanase] but not pectinase (polygalacturonase). EPS was composed solely of glucose in 1-->3 linkages; hence it is a (1-->3)beta-d-glucan (callose).
Plant Physiol 1990 Sep
PMID:Aluminum Ions Induce Oat Protoplasts to Produce an Extracellular (1-->3)beta-d-Glucan. 1666 79

After a brief period of biotrophic growth, the anthracnose fungus Colletotrichum lindemuthianum (Sacc. et Mgn.) Bri et Cav. develops extensively in bean leaf cells, causing severe wall alterations and death of the host protoplast. Aplysia gonad lectin, a polygalacturonic acid-binding agglutinin, was complexed to gold and used to study the extent of pectin breakdown during the necrotrophic phase of the infection process. In view of its specific binding properties for the endopolygalacturonase produced by C. lindemuthianum, a polygalacturonase-inhibiting protein isolated from bean cell walls was successfully tagged with gold particles and used for localizing the sites of enzyme accumulation in infected host tissues. The basal level of endopolygalacturonase produced by C. lindemuthianum grown in culture was found to increase severalfold when the fungus developed in host plant tissues. The enzyme was able to diffuse freely in the host cell wall, causing drastic degradation of the pectic material of primary walls and middle lamella matrices. The enzymatic alteration of plant cell walls was accompanied by the release of pectic fragments and by the accumulation of pectic molecules at specific sites, such as intercellular spaces and aggregated cytoplasm of infected host cells. The occurrence of pectic molecules at those sites where fungal growth is likely to be restricted is discussed in relation to their origin and their implication in the plant's defense system.
Plant Physiol 1991 Sep
PMID:Cell Surface Interactions between Bean Leaf Cells and Colletotrichum lindemuthianum: Cytochemical Aspects of Pectin Breakdown and Fungal Endopolygalacturonase Accumulation. 1666 76

This study addresses some microbial inactivation phenomena induced by high pressure CO2 over micro-organisms and enzymes. The activity of four selected enzymes was measured before and after treatment with CO2 under pressure in both buffer solutions and natural cellular environment (E. coli cells and tomato paste). Results are reported for acid phosphatase, alkaline phosphatase, ATPase, and pectinase at different conditions of temperature, CO2 pressure, and treatment time (32-40 degrees C, 85-150 bar, 30-70 min). The results obtained show that the high pressure CO2 treatment induces an inactivation of cellular enzymatic activity higher than the one caused on the same enzymes in solution. However, the measured activity difference is not caused by a damage at the enzymes molecular level but is a consequence of the permeabilization of the cellular envelopes which leads to a release of unmodified enzymes from the cells with simultaneous drop of enzymatic cellular activity. The reported data suggest that the bacterial cell death is probably due not to a selective effect of high pressure CO2 treatment but to simultaneous detrimental action of CO2 on cellular membrane and cell wall.
Biotechnol Bioeng 2006 Sep 05
PMID:A study on the inactivation of micro-organisms and enzymes by high pressure CO2. 1673 96


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