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 new method for detecting enzymes produced by fungal spores during germination is described here. With this method, the production of enzymes such as protease, cellulase, or pectinase can be correlated with the extent of spore germination. Germination is studied in vitro on agar-based media containing protein, cellulose, or pectin. The spores are immobilized on a permeable membrane mounted on the substrate-containing medium. At various times after inoculation the membrane-bound spores are removed and the medium is stained. The extent of germination is assessed by microscopic examination of the spores and the presence of active hydrolytic enzymes is revealed by the staining. The staining methods are sensitive; detection limits are 1 X 10(-3) unit of cellulase; 2 X 10(-4) unit of protease; 3 X 10(-3) unit of pectin lyase; 3.5 units of polygalacturonase; 2 X 10(-3) unit of pectin methyl esterase. The method has been demonstrated by studying the production of enzymes by germinating conidia of Botrytis cinerea. Cellulase and protease were present before any spores germinated. Pectin lyase was first observed when at least 80% of the spores had germinated. Pectin methyl esterase and polygalacturonase were not produced by the spores.
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PMID:Plate assay for determining the time of production of protease, cellulase, and pectinases by germinating fungal spores. 391 30

The transfer of a methyl group from S-adenosyl-L-methionine onto the carboxyl group of alpha-1,4-linked-galactosyluronic acid residues in the pectic polysaccharide homogalacturonan (HGA) is catalyzed by an enzyme commonly referred to as pectin methyltransferase. A pectin methyltransferase from microsomal membranes of tobacco (Nicotiana tabacum) was previously characterized (F. Goubet, L.N. Council, D. Mohnen [1998] Plant Physiol 116: 337-347) and named HGA methyltransferase (HGA-MT). We report the solubilization of HGA-MT from tobacco membranes. Approximately 22% of the HGA-MT activity in total membranes was solubilized by 0.65% (w/v) 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonic acid containing 1 mM dithioerythritol. The addition of phosphatidylcholine and the methyl acceptors HGA or pectin (30% degree of esterification) to solubilized enzyme increased HGA-MT activity to 35% of total membrane-bound HGA-MT activity. Solubilized HGA-MT has a pH optimum of 7.8, an apparent K(m) for S-adenosyl-L-methionine of 18 microM, and an apparent V(max) of 0. 121 pkat mg(-1) of protein. The apparent K(m) for HGA and for pectin is 0.1 to 0.2 mg mL(-1). Methylated product was solubilized with boiling water and ammonium oxalate, two conditions used to solubilize pectin from the cell wall. The release of 75% to 90% of the radioactivity from the product pellet by mild base treatment showed that the methyl group was incorporated as a methyl ester rather than a methyl ether. The fragmentation of at least 55% to 70% of the radiolabeled product by endopolygalacturonase, and the loss of radioactivity from the product by treatment with pectin methylesterase, demonstrated that the bulk of the methylated product produced by the solubilized enzyme was pectin.
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PMID:Solubilization and partial characterization of homogalacturonan-methyltransferase from microsomal membranes of suspension-cultured tobacco cells. 1048 84

The enterobacterium Erwinia amylovora is a devastating plant pathogen causing necrotrophic fire blight disease of apple, pear, and other rosaceous plants. In this study, we used a modified in vivo expression technology system to identify E. amylovora genes that are activated during infection of immature pear tissue, a process that requires the major pathogenicity factors of this organism. We identified 394 unique pear fruit-induced (pfi) genes on the basis of sequence similarity to known genes and separated them into nine putative function groups including host-microbe interactions (3.8%), stress response (5.3%), regulation (11.9%), cell surface (8.9%), transport (13.5%), mobile elements (1.0%), metabolism (20.3%), nutrient acquisition and synthesis (15.5%), and unknown or hypothetical proteins (19.8%). Known virulence genes, including hrp/hrc components of the type III secretion system, the major effector gene dspE, type II secretion, levansucrase (lsc), and regulators of levansucrase and amylovoran biosynthesis, were upregulated during pear tissue infection. Known virulence factors previously identified in E. (Pectobacterium) carotovora and Pseudomonas syringae were identified for the first time in E. amylovora and included HecA hemagglutinin family adhesion, Peh polygalacturonase, new effector HopPtoC(EA), and membrane-bound lytic murein transglycosylase MltE(EA). An insertional mutation within hopPtoC(EA) did not result in reduced virulence; however, an mltE(EA) knockout mutant was reduced in virulence and growth in immature pears. This study suggests that E. amylovora utilizes a variety of strategies during plant infection and to overcome the stressful and poor nutritional environment of its plant hosts.
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PMID:Identification of Erwinia amylovora genes induced during infection of immature pear tissue. 1629 82

Molecular cloning of polygalacturonase (PG; EC 3.2. 1.15) from fruits of tomato (Lycopersicon esculentum Mill cv Rutgers) was accomplished by constructing a cDNA library from turning stage poly(A)(+) RNA in lambdagtll and immunoscreening with polyclonal antibodies raised against purified PG2. Both PG cDNA and antibody probes were used to quantify changes in PG gene expression in pericarp from normal, mutant, and heterozygous genotypes. Results show that PG mRNA, protein, and enzyme activity sequentially peak at the turning, ripe, and red ripe stages of Rutgers pericarp ripening, respectively. PG gene expression was attenuated greatly (0-15% of normal on a gram fresh weight basis) for PG mRNA, protein, and enzyme activity in five ripening-impaired mutants (rin, nor, Nr, Gr, and Long Keeper) tested. Maximum expression of the PG gene in heterozygotes of rin, nor, Nr, Gr, and Long Keeper (crosses with Rutgers) at the mRNA level was about 25, 13, 17, 5, and 62% of the Rutgers turning stage, at the protein level was about 166, 110, 15, 6, and 104% of the Rutgers ripe stage, and at the enzyme activity level was about 69, 37, 4, 1, and 50% of the Rutgers red ripe stage, respectively. No PG gene expression was found in preclimacteric fruits or vegetative tissues. PG mRNA was localized on both free and membrane-bound polyribosomes of ripening pericarp. In addition to transcriptional regulation, mechanisms contributing to mRNA stability, delayed protein accumulation, and posttranslational modifications may play important roles in the overall accumulation of PG activity during fruit ripening.
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PMID:Temporal regulation of polygalacturonase gene expression in fruits of normal, mutant, and heterozygous tomato genotypes. 1666 1