• Journal of the Korean Society of Food Science and Nutrition
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• v.20 no.5
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• pp.488-493
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• 1991

The characteristics of endogenous and exogenous polygalacturonase(PG) produced from L. acidophilus were investigated as one of the serial studies on the fermentation of Chinese cabbage kimchi using L. acidophilus. Apparent molecular weigth of endogenous and exogenous PG were estimated to be 420,000 and 500,000 daltons by the method of gel filtration and Vmax of the enzymes 8.0 and $0.3{\mu}mol$ galacturonic acid/ml/30min, respectively and Km of the enzymes were 4.0mg/ml. The optimum temperature, pH and salt concentration of the both enzymes were the same and appeared to $30^{\circ}C$, 5.5 and 2~3%, respectively. The activities of the endogenous and exogenous PG all were severely decreased by increasing of temperature to $90^{\circ}C\;from\;60^{\circ}C$ and its remained activities at $60^{\circ}C\;and\;90^{\circ}C$ were 50%, 58%, and 19%, 5%, 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.

• Journal of Microbiology and Biotechnology
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• v.20 no.7
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• pp.1077-1085
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• 2010

With an emphasis on its thermal behavior with different pHs and salts, the kinetic and thermodynamic parameters of the purified polygalacturonase (PG) from E. carotovora subsp. carotovora (Ecc) BR1 were studied, as the characterization of an enzyme is significant in the context of burgeoning biotechnological applications. The thermodynamic parameters for polygalacturonic acid hydrolysis by the purified PG were ${\Delta}H^*$=7.98 kJ/mol, ${\Delta}G^*$=68.86 kJ/mol, ${\Delta}S^*$=-194.48 J/mol/K, ${\Delta}G_{E-S}$=-1.04 kJ/mol, and ${\Delta}G_{E-T}$=-8.96 kJ/mol. In addition, its turnover number ($k_{cat}$) was 21/sec. The purified PG was stable within a temperature range of $20-50^{\circ}C$ and was deactivated at $60^{\circ}C$ and $70^{\circ}C$. The thermodynamic parameters (${\Delta}H^*$, ${\Delta}G^*$, ${\Delta}S^*$) for the irreversible inactivation of the PG at different temperatures ($30-60^{\circ}C$) were determined, where the effectiveness of various salts and different pHs (4-8) for the thermal stability of the PG were also characterized. The efficacy of various salts for the thermal stability of the PG was in the following order: $MgCl_2$ > $BaCl_2$ > KCl > $CaCl_2$ >NaCl. Therefore, the present work presents the biochemical, substrate hydrolysis thermodynamics and the thermal stabilization parameters of the PG from Ecc.

• Korean Journal of Breeding Science
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• v.42 no.5
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• pp.481-487
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• 2010

The ripening behavior of three apple cultivars, 'Tsugaru', 'Hongro' and 'Fuji' was distinctive and the involvement of POLYGALACTURONASE(PG) in the fruit softening process was confirmed to be ethylene dependent. Fruit softening is genetically coordinated by the action of several cell wall enzymes, including PG which depolymerizes cell wall pectin. Also, loss of firmness is associated with increasing of the ripening hormone, ethylene. In this work, climacteric ripening of three apple cultivars, Tsugaru, Hongro and Fuji, producing different ethylene levels and ripening responses, was examined. Correspondingly in Fuji, a linear and basal ethylene level was observed over the entire period of measurements, and Tsugaru and Hongro displayed a typical climacteric rise in ethylene production. Transcript accumulation of genes involved in ethylene biosynthesis (MdACS3 and MdACO1) and MdPG1 was studied in Tsugaru, Hongro and Fuji cultivars. Expression of MdACO1 transcripts was shown in all three ripened apple fruits. However, the MdACS3 and MdPG1 were transcribed differently in these cultivars. Comparing the MdPG1 of 'Tsugaru', 'Hongro' and 'Fuji', structural difference was discovered by genomic Southern analysis. Overall results pointed out that MdACS3 and MdPG1 play an important role in regulation of fruit ripening in apple cultivar.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.2
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• pp.228-233
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• 2001

This study was carried out to characterize the enzymatic properties and effectiveness on the firmness of pectinesterase(PE) and polygalacturonase(PG) which are present in carrot cell wall, and to determine the blanching condition of raw carrot. Crude enzyme was extracted from carrots and used as PE and PG. The optimum pH of PE and PG activity were 7.0 and 5.0, respectively. NaCl enhanced PE and PG activities, particularly at 0.15 M and 0.10 M, respectively. Although the optimum temperature of PG ($70^{\circ}C$) was higher than that of PE ($50^{\circ}C$), PE ($Z-value=8.76^{\circ}C$) was more heat-stable than PG($Z-value=6.67^{\circ}C$). Blanching condition was determined as at $55^{\circ}C$ for 60 min in 0.03 M $CaCl_2$, 0.1 M NaCl and pH 7.0 from measuring firmness after blanching at various temperature ($50~70^{\circ}C$) and time (5~60 min).

• 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.

• Journal of Microbiology and Biotechnology
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• v.32 no.4
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• pp.464-472
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• 2022

An endo-polygalacturonase (endo-PGase) exhibiting excellent performance during acidic fruit juice production would be highly attractive to the fruit juice industry. However, candidate endo-PGases for this purpose have rarely been reported. In this study, we expressed a gene from Penicillium oxalicum in Pichia pastoris. The recombinant enzyme PoxaEnPG28C had an optimal enzyme activity at pH 4.5 and 45℃ and was stable at pH 3.0-6.5 and < 45℃. The enzyme had a specific activity of 4,377.65 ± 55.37 U/mg towards polygalacturonic acid, and the K_m and V_max values of PoxaEnPG28C were calculated as 1.64 g/l and 6127.45 U/mg, respectively. PoxaEnPG28C increased the light transmittance of orange, lemon, strawberry and hawthorn juice by 13.9 ± 0.3%, 29.4 ± 3.8%, 95.7 ± 10.2% and 79.8 ± 1.7%, respectively; it reduced the viscosity of the same juices by 25.7 ± 1.6%, 52.0 ± 4.5%, 48.2 ± 0.7% and 80.5 ± 2.3%, respectively, and it increased the yield of the juices by 24.5 ± 0.7%, 12.7 ± 2.2%, 48.5 ± 4.2% and 104.5 ± 6.4%, respectively. Thus, PoxaEnPG28C could be considered an excellent candidate enzyme for acidic fruit juice production. Remarkably, fruit juice production using hawthorn as an material was reported for the first time.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.5
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• pp.796-802
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• 1995

Oyijangachi, a traditional Korean brinded cucumber, was prepared by brinning the cucumbers in five different solutions for 48 hrs and then, was dipped into dipping sources(Kochujang, Doenjang and Ganjang) for 30 days of aging. Firmness, calcium content and enzyme activities(pectinesterase and polygalacturonase) changes were measured among the cucumbers which were treated by five different solutions during aging. The firmness of Kochujang Oyijangachi were the lowest after 10 days of aging for all from the five brining solutions because of "hollow phenomena" of cucumbers. Calcium contents of cucumbers after dipping into the five solutiosn increased as calcium content of the solutions increased and also increased when the cucumbers dipped into the dipping bases(Kochujang, Doenjang and Ganjang) because of calcium migration from the dipping sources into the cucumbers during aging. The calcium contents of the three dipping bases were ranged from 70mg% to 120mg% of Ca. The activity of polygalacturonase in the Oyijangachi decreased generally during aging and decreased rapidly during initial 5 days of aging. The activity of pectinesterase of cucumbers treated with 12% salts solutions(treatment 3, 4 and 5) were higher than those of cucumbers treated with 6% salts solutions(treatment 1 and 2).

• 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 $50^{\circ}C$.

• Current Research on Agriculture and Life Sciences
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• v.4
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• pp.42-49
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• 1986

The changes in pectinesterase (PE) and polygalacturonase (PG) activities were investigated during maturation and ripening of tomato fruits. PG was isolated from ripe tomatoes and purified by using DEAE-sephadex A-50 column chromatography. Its property was examined by general methods. PE activity was increased during maturation and then peaked at the on set of color change. PG activity was not detectable in mature green tomato fruits but increased during softening. Slab electrophoresis of the crude enzyme isolated from ripe tomatoes shoed 6 bands. Two polygalacturonase (PGI, PGII) were separated from crude enzyme of ripe tomatoes by chromatography on DEAE-sephadex A-50. PGI and PGII were purified by 61 fold and 98 fold by the present procedure, respectively. The Rm values of partially purified PGI and PGII were estimated to be 0.25 and 0.31, respectively. The optimum temp, and pH of PGI activity were $37^{\circ}C$ and pH 4.5, while those of PGII activity were $40^{\circ}C$ and pH 4.7, respectively. Isozyme PGI activity was the most stable at pH 4.3 and retained 50% of its activity when exposed at $78^{\circ}C$ for 5 min.