• The Korean Journal of Mycology
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• v.22 no.4
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• pp.298-308
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• 1994

The properties of polygalacturonase by Ganoderma lucidum in liquid culture were investigated. The enzyme was composed of an endo- and an exo-polygalacturonase. The endo- and exo-polygalacturonase were purified approximately 56 and 9.2-fold, respectively, through ammonium sulfate fractionation, gel filtration on Biogel P-100, anion exchange chromatography on DEAE-cellulose, gel chromatography on Sephadex G-150 and re-gel chromatography on Sephadex G-150. The endo- and exo-polygalacturonase had higher affinity for apple pectin than for citrus pectin or pectic acid. The Km values of the endo- and exo-polygalacturonase for apple pectin, determined on the Lineweaver-Burk plot, were 1.44 and 10.6 mg $ml^{-1}$ for apple pectin, respectively. Purified endo-polygalacturonase was found to be homogeneous electrophoretically and had a molecular weight of 54,000 estimated on SDS polyacrylamide gel. The optimal pH for the activity of the enzymes was 4.0. The endo- and exo-polygalacturonase were stable in the pH range of 4.0 to 6.0 and 3.5 to 5.5, respectively. The optimal temperatures of the endo- and exo-polygalacturonase were 40 and $60^{\circ}C$, respectively. The exo-polygalacturonase was more resistant to heat than the endo-polygalacturonase, requiring heating for 40 min at $80^{\circ}C$ for complete inactivation. The activity of the endo-polygalacturonase was increased by $Ca^{++}$ and $Mn^{++}\;ions$, while that of the exo-polygalacturonase was increased by $Ca^{++}\;ion$ only, and was not affected by $Mn^{++}\;ion$.

• The Korean Journal of Mycology
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• v.26 no.2 s.85
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• pp.281-286
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• 1998

Ganoderma lucidum produced the potent pectolytic enzymes for clarifying cloudy fruit juice. Among the purified polygalacturonases (endo- and exo-polygalacturonase), endo-polygalacturonase had a good effect on juice clarification. The optimum temperature and concentration of endo-polygalacturonase for the juice clarification were $40^{\circ}C$ and 4 unit/5 ml juice, respectively. The apple juice was almost completely clarified at $40^{\circ}C$ for 60 min. It was suggested that culture filtrate of Ganoderma lucidum or it's ammonium sulfate fraction should be used as a good source of pectolytic enzyme for juice clarification.

• Korean journal of applied entomology
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• v.13 no.1 s.18
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• pp.1-10
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• 1974

The activities of pectolytic and cellulolytic enzymes produced from slices of ginseng root infected with Cylindrocarpon destructains(Zins.) Scholtern were proportional to each concentration and reaction time. Activities of cellulase(Cx), endo-polygalacturonase(endo-PG), endo-polymethylg-alacturonase(endo-PMG), exo-polygalacturonase(exe-PG), and exe-polymethylgalacturonase(exo-PMG) were maximum on the 4th day after inoculation. No endo-PG and endo-PMG were detected at the first and second days, while exo-PG exo-PMG were active. On the 6th day, all pectic enzymes were completely lost, whereas Cx remained at a high concentration. pH optima of Cx, endo-PG, endo-PMG, exo-PG, and exo-PMG were 6.0, 5.5, 8.0, 7.0 to 7.5, and 8.5, respectively. Temperature optima of Cx, endo-PG, endo-PMG exo-PG, and exo-PMG were $66^{\circ}C\;53^{\circ}C\;41^{\circ}C\;37^{\circ}C\;and\;40^{\circ}C$, respectively. Cx was only inhibited by $0.05M\; Hg^{++}$ among 16 ions tested. Inhibitory effects of ions on pectolytic enzymes varied, however$M Fe^{+++}\;and\;0.05M\;Al^{+++}$ were the best in general. Among 8 fungicides, none of them inhibited all the enzymes studied at $0.1\%$, active ingredients. Exo-PG were highly inhibited by all of the fungicides, of which difolatan was the most inhibitory to all the pectic enzymes. $Ca^{++}\; at\; 0.02M\; and\;Fe^{+++}\;at\;0.02M$ completely inhibited all the pectolytic enzymes, and Cx was inhibited $30\%$ and $70\%$ at the same concentration, respectively Formalin almost inhibited exo-PG and exe-PMG at $0.8\%$ but not the other enzymes especially Cx. Difolatan at $0.8\%$ inhibited all the enzymes concerned above $80\%$. The cellulolytic and pectolytic enzymes of C. destructans must be closely associated with the ginseng root rot and should be inhibited to control the disease effectively.

• Korean Journal of Food Science and Technology
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• v.16 no.1
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• pp.41-46
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• 1984

The pectic enzymes produced from Aspergillus niger were separated into three fractions (F-A, F-I and F-II) by means of Sephadex and DEAF-Sephadex column chromatography. Each enzyme fraction was characterized by determining viscosity change and reducing surgar of the pectic acid-enzyme mixture and analyzing thin layer chromatogram of the reaction products. F-I rapidly reduced the viscosity of pectic acid solution and released reducing groups in a random manner so that appeared to be an endo-polygalacturonase (endo-PG). The optimum pH of endo-PG for viscosity reducing activity was 4.2 and that for releasing reducing surgar was 4.7. In the thermal inactivation of endo-PG of $30-45^{\circ}C$, the enthalpy of activation was 217.3 kj/mole and z-value was $7.5^{\circ}C$. F-II and F-A were determined as endo-polymethylgalacturonase and exo-polygalacturonase, respectively.

• Journal of Microbiology and Biotechnology
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• v.33 no.4
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• pp.533-542
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• 2023

Exo-polygalacturonase (exo-PG) hydrolyzes pectin acids and liberates mono-galacturonate, which plays an important role in juice extraction, and has rarely been reported. Exo-PG (AfumExoPG28A) from Aspergillus fumigatus belongs to the glycoside hydrolase 28 family. In this study, its gene was cloned and the protein was expressed and secreted in Pichia pastoris with a maximal activity of 4.44 U/ml. The optimal temperature and pH of AfumExoPG28A were 55℃ and 4.0, respectively. The enzyme exhibited activity over almost the entire acidic pH range (>20.0% activity at pH 2.5-6.5) and remained stable at pH 2.5-10.0 for 24 h. The K_m and V_max values of AfumExoPG28A were calculated by the substrate of polygalacturonic acid as 25.4 mg/ml and 23.6 U/mg, respectively. Addition of AfumExoPG28A (0.8 U/mg) increased the light transmittance and juice yield of plantain pulp by 11.7% and 9%, respectively. Combining AfumExoPG28A (0.8 U/mg) with an endo-PG (0.8 U/mg) from our laboratory, the enzymes increased the light transmittance and juice yield of plantain pulp by 45.7% and 10%, respectively. Thus, the enzyme's potential value in juice production was revealed by the remarkable acidic properties and catalytic activity in fruit pulp.

• The Korean Journal of Mycology
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• v.16 no.2
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• pp.64-69
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• 1988

Isoates with changed pathogenicity were selected among iprodione-resistant Alternaria mali to investigate any relationship between their pectolytie enzyme activity and pathogenicity. In artificial medium, strongly pathogenic isolates $S_1$, and $R_3$ showed higher enzyme activity than weakly pathogenic isolate $R_8$.Activity of endo-polymethylgalacturonase and end-o-polygalacturonase was more than 3 times. But activity of pectin methylesterase and pectin Iyase by isolaste $S_1$ was higher than those by $R_3$ and $R_8$ isolates. In apple medium dialyzed against distilled water, activity of enzyme by each isolate was increased but growth of each isolate was reduced. When iprodione was added to the medium, enzyme activity and growth of isolate $S_1$, were reduced but strongly pathogenic isolate .$R_3$ among iprodione-resistant ones showed increased enzyme activity except for exo-polygalacturonase in dialyzed apple medium.

• The Korean Journal of Mycology
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• v.19 no.2
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• pp.143-147
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• 1991

Botryosphaeria dothidea causing apple fruit rot was cultured in pectin-polypectate mine­raI salts or apple mediumss, to investigate pectolytic enzyme production and activity. Exo-polygalactu­ronase(PG) and exo-polymethylgalacturonase (PMG) in apple medium showed maximum of activity to 6.4 and 7.2 units at six days of culture, respectively. Their maximum activity in pectin-polypectate mineral salts medium was 5.9 and 5.3 units at eight days of culture lower than in apple medium respectively. Endo-PG and endo-PMG in pecin-polypectate mineral salts medium were maximum of activity to 4.4 and 16.2 units at six and eight days of culture, respectively, but activities in apple medium were 3.2 and 6.7 units at eight days of culture. Activity of polygalacturonate-trans-­eliminase(PGTE) and pectinmethyl-trans-eliminase(PMTE) was higher in pectin-polypectate mineral salts medium than in apple medium. Fungal growth was maximum at six and eight days of culture in pectin-polypectate mineral salts and apple medium, respectively.

• The Korean Journal of Mycology
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• v.22 no.4
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• pp.286-297
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• 1994

The optimum nutritional and cultural conditions of polygalacturonase by Ganoderma lucidum in liquid culture were studied. The optimal temperature, pH, and the duration of culture for production of the enzyme was $30^{\circ}C$, 5.5 and 14 days, respectively. The maximal production of the enzyme was obtained in a synthetic medium containing 10 g of pectin, 10 g of soluble starch, 1 g of yeast extract, 2 g of peptone, 1 g of phenylalanine, 2 g of $KH_2PO_4$, 0.2 g of $MgSO_4{\cdot}7H_2O$, 0.05 g of $CaCI_2$ and 100 g of $thiamin{\cdot}HCI$ in 1000 ml of distilled water.

• Korean Journal of Agricultural Science
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• v.12 no.2
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• pp.324-332
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• 1985

Aspergillus niger B-15 with strong Endo-polygalacturonase (Endo-PG) activities was selected out from a total of 1,573 fungal strains isolated from various testing materials. A mutant strain, U-46, was obtained from the Aspergillus niger B-15 by repeated irradition of ultra-violet light. The objectives of the study were to investigate the fungal properties of the parental and mutant strains obtained and to study the condition of enzyme production and reaction. The results obtained are summarized as follows: 1. The size of conidial head of the U-46 mutant was smaller than that of the parental strains, B-15 and the length of the conidiophore was also shorter than that of the parental strains. 2. The optimum conditions for the Endo-PG production of the parental B-15 strain in the wheat bran Koji were obtained when 40% of water was added to the wheat bran and the temperature was 30 to $35^{\circ}C$. However, the best condition for the mutant U-46 strain was attained when 60 to 70% of water was added and the temperature was $35^{\circ}C$. The optimum growing periods were two to three days for both parental and mutant strains. 3. Under the optimum producing conditions of each strains, the enzymatic activity of the mutant U-46 was 20 times higher than the Endo-PG of the parental strain, B-15. 4. When both strains were cultured in the wheat bran Koji containing 60% of water at $35^{\circ}C$ for three days, the mutant strain. U-46, was about 46 times higher in the Endo-PG activity and about 18 times greater in Exo-PG activity than the parental strain, B-15. The activities of cellulase, $\alpha$-amylase, and glucoamylase were also highly increased in the mutant strain. 5. The mutant strain, U-46, increased its Endo-PG activity up to 20% over that of ordinary case when 1.2 to 1.5% of ammonium sulphate was added to the wheat bran. 6. The optimum condition for Endo-PG activity of crude enzyme of the mutant strain, U-46, was attained when pH of reaction solution was 4.0 to 4.5 and the temperature was $50^{\circ}C$.

• The Plant Pathology Journal
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• v.29 no.3
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• pp.234-241
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• 2013

Polygalacturonase (PG) gene is a typical gene family present in eukaryotes. Forty-nine PGs were mined from the genomes of Neurospora crassa and five Aspergillus species. The PGs were classified into 3 clades such as clade 1 for rhamno-PGs, clade 2 for exo-PGs and clade 3 for exo- and endo-PGs, which were further grouped into 13 sub-clades based on the polypeptide sequence similarity. In gene structure analysis, a total of 124 introns were present in 44 genes and five genes lacked introns to give an average of 2.5 introns per gene. Intron phase distribution was 64.5% for phase 0, 21.8% for phase 1, and 13.7% for phase 2, respectively. The introns varied in their sequences and their lengths ranged from 20 bp to 424 bp with an average of 65.9 bp, which is approximately half the size of introns in other fungal genes. There were 29 homologous intron blocks and 26 of those were sub-clade specific. Intron losses were counted in 18 introns in which no obvious phase preference for intron loss was observed. Eighteen introns were placed at novel positions, which is considerably higher than those of plant PGs. In an evolutionary sense both intron loss and gain must have taken place for shaping the current PGs in these fungi. Together with the small intron size, low conservation of homologous intron blocks and higher number of novel introns, PGs of fungal species seem to have recently undergone highly dynamic evolution.