• BMB Reports
• /
• v.45 no.6
• /
• pp.342-347
• /
• 2012

Plant mitochondria possess alternative respiratory pathways mediated by the type II NAD(P)H dehydrogenases and alternative oxidases. Here, E3 SUMO ligase was shown to regulate alternative respiratory pathways and to participate in the maintenance of carbon and nitrogen balance in Arabidopsis. The transcript abundance of the type II NAD(P)H dehydrogenases NDA2 and NDB2 and alternative oxidases AOX1a and AOX1d genes was low in siz1-2 mutants compared to that in wild-type. The addition of nitrate or ammonium resulted in a decrease or an increase in the expression of the same gene families, respectively, in both wild-type and siz1-2 mutants. The amount of free sugar (glucose, fructose and sucrose) was lower in siz1-2 mutants than that in wild-type. These results indicate that low nitrate reductase activity due to the AtSIZ1 mutation is correlated with an overall decrease in alternative respiration and with a low carbohydrate content to maintain the carbon to nitrogen ratio in siz1-2 mutants.

• Applied Microscopy
• /
• v.24 no.2
• /
• pp.26-36
• /
• 1994

To investigate the effects of mercuric chloride ($HgCl_2$) on the differentiation in the cerebral neuron of chick embryo 7 days, the ultrastructural changes in nerve cells injected with a various doses of mercuric chloride were observed with transmission electron microscope. The enzyme activity of the some dehydrogenases, and adenosine triphophate (ATP) were also analyzed. The results obtained are as follows; The ultrastructural changes in 1.0mg-injected group, the nuclear envelope were irregular, and the RER, Golgi complexes and mitochondria were not well developed. In 2.0mg-injected group, the nuclear envelope were partly destroyed or detached, and mitochondria were decreased in number and their cristae were destroyed, too. The RER and Golgi complexes were less developed than those of the normal groups. In general, the activities of dehydrogenases were declined by increasing the dose of mercuric chloride. Lactate dehydrogenase (LDH) activity fatted to below 85% of the normal group in 1.0mg-injected group, and 69% in 2.0mg-injected group. Malate dehydrogenase (MDH) activity was decreased greatly to 76% in 2.0mg-injected group. Succinate dehydrogenase (SDH) activity fatted to 85% in 1.0mg-injected group, and 74% in 2.0mg-injected group. ATP content in 1.0mg-injected group was almost near to the normal level, but it was increased significantly in 2.0mg-injected group.

• Journal of the Korean Chemical Society
• /
• v.20 no.5
• /
• pp.406-416
• /
• 1976

A series of $N^1$-alkylnicotinamide chlorides, $N^1$-methyl-to $N^1$-dodecylnicotinamides inclusive were studied with rabbit muscle L-${\alpha}$-glycerophosphate dehydrogenase to investigate the possibility of reversible and irreversible inactivation of the pyridine-linked dehydrogenases by the coenzyme-competitive inhibitor derivatives. The inhibition of the enzyme by $N^1$-alkylnicotinamide chlorides was demonstrated to be reversible at the dilute concentration of the inhibitors but this reversible inhibition was found to be followed by an irreversible time-dependent inactivation measuable at high concentrations of the inhibitors. The properties of this time-dependent inactivation were discussed on the basis of the denaturation of the enzyme by the binding of small micelle-like structures formed at higher concentrations of the inhibitors.

• The Korean Journal of Zoology
• /
• v.17 no.4
• /
• pp.163-166
• /
• 1974

Malate dehydrogenases of ten bivalved mollusks consist of one or two isozyme, which are species-spcific. It is concluded that the electrophoretic character of the enzyme is available for identification of these ten bivalves.

• Archives of Pharmacal Research
• /
• v.27 no.5
• /
• pp.570-575
• /
• 2004

2-Hydroxymuconic semialdehyde (2-HMS) dehydrogenase catalyzes the conversion of 2-HMS to 4-oxalocrotonate, which is a step in the meta cleavage pathway of aromatic hydrocarbons in bacteria. A tomC gene that encodes 2-HMS dehydrogenase of Burkholderia cepacia G4, a soil bacterium that can grow on toluene, cresol, phenol, or benzene, was overexpressed into E. coli HB 101, and its gene product was characterized in this study. 2-HMS dehydrogenase from B. cepacia G4 has a high catalytic efficiency in terms of V$_{max}$K$_{max}$ towards 2-hydroxy-5-methyl-muconic semialdehyde followed by 2-HMS but has a very low efficiency for 5-chloro-2-hydroxymuconic semialdehyde. However, the enzyme did not utilize 2-hydroxy-6-oxo-hepta 2,4-dienoic acid and 2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoic acid as substrates. The molecular weight of 2-HMS dehydrogenase from B. cepacia G4 was predicted to be 52 kDa containing 485 amino acid residues from the nucleotide sequence of the tomC gene, and it exhibited the highest identity of 78% with the amino acid sequence of 2-HMS dehydrogenase that is encoded in the aphC gene of Comamonas testosteroni TA441. 2-HMS dehydrogenase from B. cepacia G4 showed a significant phylogenetic relationship not only with other 2-HMS dehydrogenases, but also with different dehydrogenases from evolutionarily distant organisms.sms.

• Journal of Microbiology
• /
• v.35 no.3
• /
• pp.200-205
• /
• 1997

Bothl $Ca^{2+}$ and Sr$^{2+}$-containing methanol dehydrogenases (MDH) were purified to homogeneity with yields of 48% and 42%, respectively, from Methylabacillus methanolovorus sp. strain SK5. Most of the biochemical and structural properties were similar to each other. However, some differences were found: (1) although the overall shape of the absorption spectrum of Sr$^{2+}$-MDH was very similar to that of $Ca^{2+}$-MDH, the absorption intensity originating from the cofactor in Sr$^{2+}$. MDH was higher than that in $Ca^{2+}$-MDH. Small blue shift of the maximum was also observed. These are probably due to a difference in redox state of the cofactors in $Ca^{2+}$ and Sr$^{2+}$-MDH; (2) Sr$^{2+}$-MDH was more heat-stable than $Ca^{2+}$-MDH above 56$^{\circ}C$; (3) the V$_{max}$ values for the methanol-dependent activities of Sr$^{2+}$- and $Ca^{2+}$-MDH in the presence of 3 mM KCN were 2.038 and 808 nmol/mg protein/min, respectively. In addition, the $K_{m}$ values of Sr$^{2+}$ and $Ca^{2+}$ MDH for methanol were 12 and 21 $\mu$M, respectively; (4) the endogenous activity of $Ca^{2+}$-MDH was more sensitive than that of Sr$^{2+}$-MDH in the presence of cyanide; (5) Diethyl pyrocarbonate treatment increased the enzyme activities of $Ca^{2+}$- and Sr$^{2+}$-MDH 4.2- and 1.4-folds, respectively. These results indicate that Sr$^{2+}$ stabilizes the structural conformation and enhances the activity of MDH more than $Ca^{2+}$.

• Proceedings of the Plant Resources Society of Korea Conference
• /
• 2023.04a
• /
• pp.12-12
• /
• 2023

Plant biomass, or lignocellulose, is one of the most abundant natural resources on earth. Lignocellulosic biomass, such as agricultural and forestry residue, serves as a renewable feedstock for microbial cell factories due to its low price and abundant availability. However, the recalcitrance of lignocellulosic biomass requires a pretreatment process prior to microbial fermentation, from which fermentable sugars including xylose and glucose are generated along with various inhibitory compounds. The presence of furan derivatives, such as 5-hydroxymethyl-2-furaldehyde and 2-furaldehyde (furfural), hampers the microbial conversion of lignocellulosic biomass into value-added commodities. In this study, furfural tolerance was improved by investigating the detoxification mechanism in non-model yeast. The genes encoding aldehyde dehydrogenases were overexpressed to enhance furfural tolerance and resulted in improving cell growth and lipid production that can be converted into biofuel. Taken together, this approach contributes to the understanding of the reducing toxicity mechanism of furfural by the aldehyde dehydrogenases and provides a promising strategy that the use of microorganism as an industrial workhorse to treat efficiently lignocellulosic biomass as sustainable plant derivatives.

• Journal of Microbiology and Biotechnology
• /
• v.27 no.4
• /
• pp.649-659
• /
• 2017

Extremophilic microorganisms have established a diversity of molecular strategies in order to survive in extreme conditions. Biocatalysts isolated by these organisms are termed extremozymes, and possess extraordinary properties of salt allowance, thermostability, and cold adaptivity. Extremozymes are very resistant to extreme conditions owing to their great solidity, and they pose new opportunities for biocatalysis and biotransformations, as well as for the development of the economy and new line of research, through their application. Thermophilic proteins, piezophilic proteins, acidophilic proteins, and halophilic proteins have been studied during the last few years. Amylases, proteases, lipases, pullulanases, cellulases, chitinases, xylanases, pectinases, isomerases, esterases, and dehydrogenases have great potential application for biotechnology, such as in agricultural, chemical, biomedical, and biotechnological processes. The study of extremozymes and their main applications have emerged during recent years.

• Food Industry And Nutrition
• /
• v.2 no.1
• /
• pp.16-21
• /
• 1997

Microbial of enzymatical methods are suitable for production of rare monosaccharides. Using oxidation and reduction ability of Microorganisms, various rare ketoses and polyols can be produced, for example D-tagatose from galagtitol by Enterobacter agglomerans strain 221e. L-tagatose from galactitol by Klebsiella pheumonias strain 40b, L-psicose from allitol by Gluconobacter frateurii IFO 3254, D-talitol from d-tagatose by Aureobasidium pullulans strain 113B, allitol from D-psicose by Enterobacter agglomerans strain 221e and so on. We can produce various rare aldoses and ketoses using aldose isomerases, for example L-galactose from L-tagatose by D-arabnose isomerase, and L-ribose from L-ribulose by L-isomerase, and so on. D-Tagatose 3-epimerase of Pseudomonas sp. ST-24 is very useful for preparationof various rare ketoses, for example D-psicose from D-fructose, D-sorbose from D-tagatose, L-fructose, from L-psicose and so on. Using polyol dehydrogenases, aldose isomerases and D-tagatose 3-epimerase, we can design the suitable for production of a certain rare monosaccharide from a suitable substrate.

• Journal of Microbiology and Biotechnology
• /
• v.32 no.2
• /
• pp.170-175
• /
• 2022

3-Hydroxypropionic acid (3HP) is a platform chemical and can be converted into other valuable C3-based chemicals. Because a large amount of glycerol is produced as a by-product in the biodiesel industry, glycerol is an attractive carbon source in the biological production of 3HP. Although eight 3HP-producing aldehyde dehydrogenases (ALDHs) have been reported so far, the low conversion rate from 3-hydroxypropionaldehyde (3HPA) to 3HP using these enzymes is still a bottleneck for the production of 3HP. In this study, we elucidated the substrate binding modes of the eight 3HP-producing ALDHs through bioinformatic and structural analysis of these enzymes and selected protein engineering targets for developing enzymes with enhanced enzymatic activity against 3HPA. Among ten AbKGSADH variants we tested, three variants with replacement at the Arg281 site of AbKGSADH showed enhanced enzymatic activities. In particular, the AbKGSADH^R281Y variant exhibited improved catalytic efficiency by 2.5-fold compared with the wild type.