• Journal of The Korean Society of Inherited Metabolic disease
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• v.16 no.3
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• pp.135-140
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• 2016

Purpose: Galactose is metabolized to galactose-1-phosphate by galactokinase (GALK), galactose-1-phosphate uridyltransferase (GALT) and UDP-galactose-4-epimerase (GALE), and galactosemia occurs when each enzyme is deficient. In Korea, unlike foreign countries, classic galactosemia is rare and transient galactosemia due to GALK hyperactivity is reported, but studies on frequency, clinical significance, and genetic variation are lacking. In this study, we analyzed the clinical characteristics of patients with galactosemia due to GALK hyperactivity. Methods: We investigated 85 patients who had an elevated galactose level in the neonatal screening test without deficiency of enzymes at Department of Pediatrics, Seoul & Bucheon Soonchunhyang University Hospital from January 2008 to June 2016. We investigated the level of galactose, galactose-1-phosphate, GALK and duration of galactose normalization, and analyzed the correlation between GALK elevation and galactose, galactose-1-phosphate and duration of galactose normalization. And the levels of galactose, galactose-1-phosphate, and duration of galactose normalization were compared between the galactose-free formula feeding group and non-feeding group. Results: Mean age of visit was $26.7{\pm}16.1days$. Duration of galactose normalization was $35.3{\pm}20.5days$. Mean galactose level was $18.5{\pm}7.3mg/dL$ in the neonatal screening and follow-up galactose level in serum was $2.3{\pm}5.4mg/dL$. The mean value of galactose-1-phosphate was $6.0{\pm}4.7mg/dL$ and the mean GALK level was $3.84{\pm}1.28{\mu}mol/Hr/gHb$. There was no significant correlation between GALK levels and galactose levels in the neonatal screening test (P=0.351), and we analyzed the correlation between GALK levels and follow-up galactose levels in serum, there was no significant correlation (P=0.101). There was a significant correlation between GALK levels and galactose-1-phosphate (P=0.015), and the correlation between GALK levels and duration of galactose normalization was not statistically significant (P=0.176). 49% of the patients were fed galactose-free formula, and 45% were not. Galactose and galactose-1-phosphate levels in the neonatal screening test were statistically significantly higher (P=0.004, 0.034) in using galactose-free formula group. Duration of galactose normalization was not related to the use of galactose-free formula (P=0.266, 0.249). Conclusion: Galactosemia due to GALK hyperactivity seems to be a temporary phenomenon and may not require galactose restriction. More research is needed on the role of the nuclear protein, racial traits and genetic variations in Korean patients.

• Journal of Microbiology and Biotechnology
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• v.18 no.11
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• pp.1792-1796
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• 2008

Succinic acid-producing Anaerobinspirillum succiniciproducens was anaerobically grown on galactose, galactose/glucose, or galactose/lactose in order to study its galactose fermentation. Unlike a previous report, A. succiniciproducens was found to efficiently metabolize galactose as the sole carbon source at a rate of 2.4 g/g-DCW/h and produced succinic acid with as high a yield of 87% as with using glucose. When glucose and galactose were present, A. succiniciproducens metabolized both sugars simultaneously. Furthermore, when lactose and galactose coexisted, lactose did not inhibit the galactose fermentation of A. succiniciproducens. Therefore, co-utilization of galactose and other sugars can improve the productivity and economy of bio-based succinic acid processes.

• Transactions of the Korean hydrogen and new energy society
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• v.23 no.4
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• pp.397-403
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• 2012

Galactose, an isomer of glucose with an opposite hydroxyl group at the 4-carbon, is a major fermentable sugar in various promising feedstock for hydrogen production including red algal biomass. In this study, hydrogen production characteristics of galactose-glucose mixture were investigated using batch fermentation experiments with heat-treated digester sludge as inoclua. Galactose showed a hydogen yield compatible with glucose. However, more complicated metabolic steps for galactose utilization caused a slower hydrogen production rate. The existence of glucose aggravated the hydrogen production rate, which would result from the regulation of galactose-utilizing enzymes by glucose. Hydrogen produciton rate at galactose to glucose ratio of 8:2 or 6:4 was 67% of the production rate for galactose and 33% for glucose, which could need approximately 1.5 and 3 times longer hydraulic retention time than galacgtose only condition and glucose only condition, respectively, in continuous fermentation. Hydrogen production rate, Hydrogen yield, and organic acid production at galactose to glucose ratio of 8:2 or 6:4 were 0.14 mL H2/mL/hr, 0.78 mol $H_2$/mol sugar, and 11.89 g COD/L, respectively. Galactose-rich biomass could be usable for hydogen fermenation, however, the fermentation time should be allowed enough.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.214.4-215
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• 2003

In galactose metabolic pathway : there are three inborn metabolic disorders galactokinase deficiency (galactosemia type II), galactose-1-phosphate uridyl transferase(GALT) daficiency (galactosemia type I ), uridine diphosphate galactose-4-epimerase deficiency (galactosemia typeIII). Among these disorders GALT deficiency is the most severe and common. Infants with GALT deficiency fail to metabolize galactose-1-phosphate. As a consequence, galactose-1-phosphate and galactose are accumulated in blood in which GALS enzyme plays the role of a pathognomonic marker. (omitted)

• Journal of Microbiology and Biotechnology
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• v.16 no.1
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• pp.84-91
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• 2006

A Saccharomyces cerevisiae pgs1 nulI mutant, which is deficient with phosphatidyl glycerol (PG) and cardiolipin (CL) biosynthesis, grows well on most fermentable carbon sources, but fails to grow on non-fermentable carbon sources such as glycerol, ethanol, and lactate. This mutant also cannot grow on galactose medium as the sole carbon source. We found that the incorporation of $[^{14}C]-galactose$, which is the first step of the galactose metabolic pathway (Leloir pathway), into the pgs 1 null mutant cell was extremely repressed. Exogenously expressed PGS1 (YCpPGS1) under indigenous promoter could completely restore the pgs1 growth defect on non-fermentable carbon sources, and dramatically recovered $[^{14}C]-galactose$ incorporation into the pgs1 mutant cell. However, PGS1 expression under the GALl promoter $(YEpP_{GAL1}-PGS1myc)$ could not complement pgs1 mutation, and the GAL2-lacZ fusion gene $(YEpP_{GAL2}-lacZ)$ also did not exhibit its $\beta-galactosidase$ activity in the pgs1 mutant. In wild-type yeast, antimycin $A(1\;{\mu}g/ml)$, which inhibits mitochondrial complex III, severely repressed not only the expression of the GAL2-lacZ fusion gene, but also uptake of $[^{14}C]-galactose$. However, exogenously expressed PGS1 partially relieved these inhibitory effects of antimycin A in both the pgs1 mutant and wild-type yeast, although it could not basically restore the growth defect on galactose by antimycin A. These results suggest that the PGSI gene product has an important role in utilization of galactose by Gal genes, and that intact mitochondrial function with PGS1 should be required for galactose incorporation into the Leloir pathway. The PGS1 gene might provide a clue to resolve the historic issue about the incapability of galactose with deteriorated mitochondrial function.

• Journal of Applied Biological Chemistry
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• v.54 no.1
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• pp.41-46
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• 2011

A galactose-fermenting yeasts, Saccharomyces cerevisiae No. 9, was selected by screening their abilities to produce carbon dioxide gas when grown on galactose. The selected strain, No. 9 and the reference strains NRRL Y-1528 which was exceptionally resistant to high concentration of substrate, were acclimated on sugars such as glucose, mannose, and galactose, and then their ethanol productivities were investigated during fermentation on these three carbon sources. Ethanol productivity of the strain No. 9 reached to the maximum levels after 18 h of fermentation and the ethanol yield was from 36 to 38% when presented as $[EtOH]_{max}/[Sugar]_{ini}(g/g)$, regardless of the conditions of acclimation. From the results obtained by acclimation and fermentation, it was concluded that the ethanol yields from galactose were not affected by the sugars acclimated. Improvements of the strain S. cerevisiae No. 9 were attempted to increase the fermentation efficiency and/or ethanol yields on high concentration of substrate by the conventional mutation methods employing methanesulfonic acid, ethyl ester (EMS). Mutants, Mut-5 (SJ1-40), -17 (LK4-25) and -24 (LK2-48) fermented galactose at the concentration of 20% in the levels of higher 39.9~51.6% than the mother strain, No. 9, however, their ethanol yields never exceeded those of the reference strain.

• Korean Journal of Food Science and Technology
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• v.22 no.7
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• pp.743-747
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• 1990

Glucose, arabinose and total non-cellulosic neutral sugar contents of alcohol-insoluble substance were increased during maturation of persimmon, but arabinose, galactose and total non-cellulosic neutral sugar contents were decreased in soft persimmon. The main non-cellulosic neutral sugars of cell wall were galactose, arabinose and glucose. Arbinose and galactose contents were decreased during maturity and this tend was remarkable in soft persimmon. Pectic fraction contained $70{\sim}82%$ of uronic acid, and galactose, arabinose and uronic acid of pectic fraction were decreased. The main non-cellulosic neutral sugars of hemicelluloses were glucose, xylose, and galactose. Galactose was decreased during maturation and postharvest, and contents of non-cellulosic neutral sugar were decreased in soft persimmon.

• Food Science and Preservation
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• v.5 no.1
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• pp.29-34
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• 1998

This study was carried out to investigate the effects of calcium and galactose treatments on ethylene productions in persimmon fruits for the study on the study of persimmon fruits. Ethylene was producted in green mature persimmon fruits treated with water, calcium and galactose after 24hrs of treatment. Ethylene productions of persimmon fiuits treated with galactose was very higher than those of persimmon fruits treated with water and calcium after 72hrs of treatment. Ethylene productions of persimmon fruits teated with water and calcium were similarly to that of persimmon fruit tested with calcium. The treatment of glucose was not effected on ethylene production of persiommn fruits. The ACC contents and ACC synthase activity in persimmon fruit treated with galactose were higher than those of other groups after 72hrs of storage, but the ACC contents and ACC synthase activity of persimmon fruits treated with calcium were lower than those of control and persimmon fruits treated with water.

• Korean Journal of Veterinary Research
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• v.34 no.4
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• pp.781-785
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• 1994

Uridine diphosphate(UDP)-galactose-4-epimerase-less mutants of Salmonella pullorum were isolated after mutagenic treatment with ethidium bromide. When isolated gal E mutants of S. pullorum A2 and D1 were grown in the presence of galactose(0.1 W/V), they exhibited marked bacteriolysis in heart infusion broth. The mutant strains were further investigated the characteristics of enzymatic activities in the Leoloir galactose pathway. Isolated A2 and D1 strains were completely deficient in UDP-galactose-4-epimerase activity. And the activity of other enzymes involved in galactose metabolism were reduced significantly.

• Journal of Plant Biology
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• v.7 no.3
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• pp.1-8
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• 1964

Exposing yeast cells with a certain genotype to different inducers, the ability of the yeast cells (Saccharomyces cerevisiae) to obtain enhanced fermentation for carbohydrates was observed. Regardless of the preexposure to any substrate, the inherent character incapable of fermenting a certain carbohydrate was maintained, while utilization of carbohydrates by the cells with a certain gene markers was varied by the previous conditions where they were exposed. Galactose was the best inducer for the cells to elaborate melibiase, even the galactose was not utilized as a substrate. Preexposure to galactose seemed to be necessary for the cells to utilize galactose and melibiose. Galactose fermentation by GA cells was enhanced by the exposure of the cells to galactose, but not to melibiose, raffinose, sucrose or glucose. Delayed fermentation of sucrose by the cells exposed to glucose or melibiose, but not to galactose, was observed. Raffinose fermentation was obtained by the cells with either SU RAF or GA ME genes, but the enhanced fermentation of raffinose seemed to be dependent on which inducer the cells were exposed previously and enzymes induced by the inducer to break either one of the linkages of raffinose molecule, the alpha0galactosidic or the beta-fructo-furanosidic.