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 method to determine the amount of galacturonic acid in blocksequence (BS) in pectin homogalacturonan (HG) is described. The method is based on a combination of endopolygalacturonase II (endo-PG II) and exopolygalacturonase (exo-PG) digestion followed by quantification of the liberated galacturonic acid monomer. The amount of monomers released is directly related to the amount of non-esterified galacturonic acid units located between two other non-esterified galacturonic acids units on the HG chain. The amount released for exo-PG digestion only corresponds to the BS located at the non-reducing end of the polymer. The difference between total- and exo-BS was calculated to be the amount of endo-BS located either within or on the reducing end of the HG. Three series of model pectins obtained by de-esterification of a high-ester pectin with either plant pectin methyl-esterase (p-PME, P-series), fungal pectin methyl-esterase (f-PME, F-series) and chemical de-esterification using base (B-series) were analysed and compared with a fully de-esterified pectic acid sample obtained from the same raw material. Clear differences for the increase of the amounts of blocksequence could be seen between de-esterification of the P- and F-series samples supporting a blockwise and a homogenous de-esterification mechanism, respectively. f-PME and base treatment showed only minor differences in the increase of galacturonic acid units in BS, despite differences seen in their methyl-esterification pattern. Differences between the amounts of galacturonic acid located in exo- and endo-BS, provided evidence for the need of a certain start side or blocklength for p-PME to de-esterify blockwise.
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PMID:Quantification of the amount of galacturonic acid residues in blocksequences in pectin homogalacturonan by enzymatic fingerprinting with exo- and endo-polygalacturonase II from Aspergillus niger. 1094 80

Most structures of neutral lipases and esterases have been found to adopt the common alpha/beta hydrolase fold and contain a catalytic Ser-His-Asp triad. Some variation occurs in both the overall protein fold and in the location of the catalytic triad, and in some enzymes the role of the aspartate residue is replaced by a main-chain carbonyl oxygen atom. Here, we report the crystal structure of pectin methylesterase that has neither the common alpha/beta hydrolase fold nor the common catalytic triad. The structure of the Erwinia chrysanthemi enzyme was solved by multiple isomorphous replacement and refined at 2.4 A to a conventional crystallographic R-factor of 17.9 % (R(free) 21.1 %). This is the first structure of a pectin methylesterase and reveals the enzyme to comprise a right-handed parallel beta-helix as seen in the pectinolytic enzymes pectate lyase, pectin lyase, polygalacturonase and rhamnogalacturonase, and unlike the alpha/beta hydrolase fold of rhamnogalacturonan acetylesterase with which it shares esterase activity. Pectin methylesterase has no significant sequence similarity with any protein of known structure. Sequence conservation among the pectin methylesterases has been mapped onto the structure and reveals that the active site comprises two aspartate residues and an arginine residue. These proposed catalytic residues, located on the solvent-accessible surface of the parallel beta-helix and in a cleft formed by external loops, are at a location similar to that of the active site and substrate-binding cleft of pectate lyase. The structure of pectin methylesterase is an example of a new family of esterases.
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PMID:Three-dimensional structure of Erwinia chrysanthemi pectin methylesterase reveals a novel esterase active site. 1116 5

Eight cold-adapted, polygalacturonase-producing yeasts belonging to four species were isolated from frozen environmental samples in Iceland. They were identified as Cystofilobasidium lari-marini, Cystofilobasidium capitatum, Cryptococcus macerans and Cryptococcus aquaticus species by sequence analysis of rDNA regions. Growth behavior of the isolates was investigated. All strains could grow at 2 degrees C. Addition of glucose to pectin-containing culture medium had a repressive effect on enzyme production except for C. aquaticus, which showed increased polygalacturonase activity. Optimal temperature for enzyme production for the Cystofilobasidium strains was 14 degrees C, while that for the Cryptococcus strains was lower. Among the isolates, C. lari-marini S3B produced highest levels of enzyme activity at pH 3.2. Preliminary characterization of the polygalacturonases in the culture supernatant showed the enzyme from Cystofilobasidium strains to be optimally active at 40 degrees C and pH 5, and that from the Cryptococcus strains at 50 degrees C and pH 4. The polygalacturonase from C. macerans started to lose activity after 1 h of incubation at 40 degrees C, while that from the other strains had already lost activity at 30 degrees C. All the strains except C. aquaticus produced isoenzymes of polyglacturonase. In addition to polygalacturonase, the Cystofilobasidium strains produced pectin lyase, C. aquaticus pectin esterase, and C. macerans pectin lyase, pectate lyase and pectin esterase.
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PMID:Cold-adapted yeasts as producers of cold-active polygalacturonases. 1276 49

Erwinia chrysanthemi causes soft-rot diseases of many plants by secreting a battery of enzymes which degrade the plant cell walls. We initiated a proteomic analysis to create a reference map of the E. chrysanthemi secretome. Extracellular proteins were isolated from E. chrysanthemi culture supernatants and resolved by two-dimensional electrophoresis. By analysis of mutants, Western blotting, and matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) 55 spots representing 25 unique proteins were identified. In uninduced conditions, we identified spots corresponding to the cellulase Cel5, the proteases PrtA, PrtB, and PrtC, the flagellin FliC, and some intracellular proteins whose presence probably resulted from spontaneous cell lysis. We identified another secreted protein, AvrL, homologous to an avirulence protein of Xanthomonas campestris. After culture in conditions inducing pectinase production, i.e., in the presence of galacturonate and plant extract, we identified spots corresponding to the endopectate lyases PelA, PelB, PelC, PelD, PelE, PelI, PelL, and PelZ, the pectin acetylesterases PaeX and PaeY, the pectin methylesterase PemA, and the polygalacturonase PehX. In the presence of other inducing compounds, we detected the rhamnogalacturonate lyase RhiE and the esterase FaeD. Analysis of mutants, altered for one type of secretion system, was performed to determine the targets of each system. The type I system Prt was necessary for the secretion of three proteases. No proteins secreted by the type III Hrp system could be detected in E. chrysanthemi supernatants. In addition to the already known substrates (eleven pectinases and one cellulase), this analysis revealed that the type II Out system mediates secretion of the esterase FaeD and of the Avr-like protein AvrL.
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PMID:The secretome of the plant pathogenic bacterium Erwinia chrysanthemi. 1537 9

The characterization of 23 Lactobacillus strains was performed. The strains were assayed for biogenic amine-forming capacity, hydrogen peroxide production, pectin esterase, cellulase and polygalacturonase production, growth rate, acidifying capacity and salt tolerance. Three strains were selected which belonged to the species, Lactobacillus brevis, Lactobacillus plantarum and Lactobacillus fermentum. Different starter cultures prepared as combinations of these three strains were assayed in pilot scale fermentations and Randomly Amplified Polymorphic DNA (RAPD) analysis, using a previously selected random primer, was applied for monitoring the inoculated strains. The course of fermentations was similar in all batches but sensorial analysis of eggplants fermented using a mixed culture of the three strains displayed the best results, and no differences were obtained when compared with commercial eggplants.
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PMID:Characterization of Lactobacillus strains and monitoring by RAPD-PCR in controlled fermentations of "Almagro" eggplants. 1597 83

A method for analysis of the component composition of multienzyme complexes secreted by the filamentous fungus Trichoderma reesei was developed. The method is based on chromatofocusing followed by further identification of protein fractions according to their substrate specificity and molecular characteristics of the proteins. The method allows identifying practically all known cellulases and hemicellulases of T. reesei: endoglucanase I (EG I), EG II, EG III, cellobiohydrolase I (CBH I), CBH II, xylanase I (XYL I), XYL II, beta-xylosidase, alpha-L-arabinofuranosidase, acetyl xylan esterase, mannanase, alpha-galactosidase, xyloglucanase, polygalacturonase, and exo-beta-1,3-glucosidase. The component composition of several laboratory and commercial T. reesei preparations was studied and the content of the individual enzymes in these preparations was quantified. The influence of fermentation conditions on the component composition of secreted enzyme complexes was revealed. The characteristic features of enzyme preparations obtained in "cellulase" and "xylanase" fermentation conditions are shown.
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PMID:New effective method for analysis of the component composition of enzyme complexes from Trichoderma reesei. 1603 8

Mature ;Bartlett' pear (Pyrus communis) fruits were ripened at 20 C. Fruits at different stages of ripeness were homogenized, and extracts of the low speed pellet (crude cell wall) were prepared. These extracts contained polygalacturonase, pectin esterase, and activity against seven p-nitrophenyl glycoside substrates. Polygalacturonase, alpha-galactosidase, and alpha-mannosidase increased in activity as the fruit ripened. Cellulase and activities against pear wall xylan and arabinan were absent from the extracts.
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PMID:Cell Wall Metabolism in Ripening Fruit: II. CHANGES IN CARBOHYDRATE-DEGRADING ENZYMES IN RIPENING ;BARTLETT' PEARS. 1666 Dec 76

The ability of six strains of Pichia anomala, four strains of Pichia kluyveri and two strains of Hanseniaspora uvarum predominant during coffee processing to produce polygalacturonase (PG), pectin esterase (PE) and pectin lyase (PL) in yeast polygalacturonic acid medium (YPA) and in coffee broth (CB) was studied. For comparison, a reference strain of Kluyveromyces marxianus CCT 3172 isolated from cocoa and reported to produce high amount of PG was included. Initial screening of PG activity using YPA medium showed that K. marxianus CCT 3172, P. anomala S16 and P. kluyveri S13Y4 had the strongest activity. Enzymatic assays showed that the four yeast species secreted PG, but none of the yeasts investigated was found to produce PE or PL. P. anomala S16 and P. kluyveri S13Y4 were found to produce higher amounts of PG when grown in CB than in YPA. When K. marxianus CCT 3172, P. anomala S16 and P. kluyveri S13Y4 were grown in YPA broth adjusted to pH of 3.0-8.0 and incubated at temperatures of 15-40 degrees C, the three yeast species secreted the highest amount of PG at pH 6.0 and at 30 degrees C. For PG secreted by K. marxianus CCT 3172 and P. anomala S16, the optimum pH and temperature for the enzymatic activity were 5.5 and 40 degrees C, respectively. On the other hand, PG produced by P. kluyveri S13Y4 showed the highest activity at pH 5.0 and 50 degrees C. Significant differences in the extracellular activity of PG were found between the yeasts species as well as between strains within same species. High amounts of PG were produced by two strains of P. anomala and P. kluyveri. It is therefore likely that strains of those two species may be involved in the degradation of pectin during coffee fermentation.
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PMID:Pectin degrading enzymes in yeasts involved in fermentation of Coffea arabica in East Africa. 1678 90

Pectic zymogram, RFLP and PCR analyses were used to characterize Rhizoctonia solani AG 3 isolates collected from diseased potatoes in South Australia. The pectic zymogram data were compared with those obtained for isolates collected from central Iran. Analyses of bands corresponding to pectin esterase and polygalacturonase revealed three zymogram subgroups (ZG) in AG 3. In addition to the previously reported ZG7 (here renamed ZG7-1), two new zymogram subgroups, ZG7-2 and ZG7-3, were identified. Of the 446 isolates tested, 50% of the South Australian and 46% of the Iranian isolates were ZG7-1. The majority of the isolates originating from stem and root cankers were ZG7-1, whereas most of the isolates designated ZG7-2 and ZG7-3 originated from tuber-borne sclerotia. Pathogenicity tests revealed that ZG7-1 generally produced fewer sclerotia and more severe cankers of underground parts of the potato plants than the other two ZGs. Two random DNA clones, one originating from an AG 3 isolate and the other from an AG 4 isolate, were used as probes for RFLP analyses of Australian isolates. The AG 3 probe, previously identified to be specific to this group, detected a high level of genetic diversity, with 11 genotypes identified amongst 50 isolates analysed. The low-copy AG 4 probe resolved three genotypes amongst 24 isolates. For 23 isolates analysed with both markers, the combined data distinguished a total of six genotypes and similarity analysis resolved the isolates into two main groups with 50% homology. PCR, using primers for the plant intron splice junction region (R1), also revealed variation. No obvious relationship among pectic zymogram groups, RFLP and PCR genotypes was observed.
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PMID:Intraspecific variation of Rhizoctonia solani AG 3 isolates recovered from potato fields in Central Iran and South Australia. 1724 57

Commercial acid-extracted sugar beet pectin was extensively hydrolysed using an endo-polygalacturonase (AnPGI from Aspergillus niger or AnPGII from A. niger or FmPG from Fusarium moniliforme) in combination with Aspergillus aculeatus pectin methyl-esterase (AaPME). The homogalacturonan-derived oligogalacturonates released were quantified by high-performance anion-exchange chromatography and their structure determined by mass spectrometry. The different endo-polygalacturonases exhibited variable tolerance towards acetyl groups. AnPGI was the most active and FmPG the less. A hypothetical homogalacturonan was constructed using the AnPGI-recovered oligogalacturonates as building blocks and the validity of the model was checked taking into account FmPG observed requirements and hydrolysis products. A blockwise repartition of the acetyl groups onto sugar beet pectin homogalacturonan is proposed.
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PMID:Evidence for a blockwise distribution of acetyl groups onto homogalacturonans from a commercial sugar beet (Beta vulgaris) pectin. 1844 41


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