• Food Science and Biotechnology
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• v.14 no.1
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• pp.117-122
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• 2005

Polyphenoloxidase (PPO) was extracted from Solanum tuberosum Jasim by various chromatographic methods and was subsequently purified and characterized. PPO was purified upto 78-fold from the crude extract. SDS-PAGE profile of the enzyme showed a major subunit of PPO with molecular weight of 40 kDa. The optimum pH and temperature for the maximum activity of PPO was 6.5 and $25^{\circ}C$, respectively. The enzyme was found to be quite stable between 10 and $40^{\circ}C$, whereas it was almost inactivated at $70^{\circ}C$ when incubated for 30 min. Substrate specificity study indicated that catechol was the most suitable substrate for PPO isolated from purple-fleshed potato with a $K_m$ value of 21.1 mM. The most effective inhibitor was ascorbic acid, followed by L-cysteine, citric acid, EDTA, and boric acid. Studies on the effect of metal ion on PPO activity showed that magnesium and copper were inhibitory, while iron and zinc ions increased the activity of PPO.

• Journal of the Korean Society of Tobacco Science
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• v.24 no.2
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• pp.113-120
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• 2002

This study was conducted to determine the smoke component changes by adding oriental, reconstituted, and expanded tobacco leaves. 7 different cigarette brands which were mixed with flue-cured, burley, oriental, reconstituted and expanded tobacco leaves were used for this study. 64 kinds of smoke components which were 6 of general components, 34 of semi-volatile and volatile components, 9 of acid components, and 15 of phenolic components were analyzed. All smoke components of mainstream smoke were changed by the different branding. As Tar, nicotine, ammonia, pH, all of acid compounds(except lacatic and glycolic acid) were decreased; HCN, levoglucosame, 4-vinyl phenol, 4-vinyl catechol, quinic acid-r-lactone, acetaldehyde, 2,3-butadiene, stylene were increased by adding oriental tobacco leaves. When the reconstituted tobaccos were added to 20%, the concentration of nicotine, all of acid compounds(except lactic. glycolic, palmitic acid) and all of phenol compounds were reduced; the concentration of ammonia, HNC, CO, aeconitrile, benzene, 2-butanone, moth-acrolene, butyronitrile, stylene, o-xylene were increased. As decreasing ammonia, pH, nicotine, all of acid compounds, all of phenol compounds, Isoprene, acetonitrile, 2-methyl-2-butene, 1,3-pentadiene, 2-nlethyl furane, ethylene cyclopentanone, ethyl bezene; increasing CO concentration were followed by adding expanded tobacco leaves.

• BMB Reports
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• v.49 no.1
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• pp.45-50
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• 2016

Salsolinol (SAL), a compound derived from dopamine metabolism, is the most probable neurotoxin involved in the pathogenesis of Parkinson's disease (PD). In this study, we investigated the modification and inactivation of human ceruloplasmin (hCP) induced by SAL. Incubation of hCP with SAL increased the protein aggregation and enzyme inactivation in a dose-dependent manner. Reactive oxygen species scavengers and copper chelators inhibited the SAL-mediated hCP modification and inactivation. The formation of dityrosine was detected in SAL-mediated hCP aggregates. Amino acid analysis post the exposure of hCP to SAL revealed that aspartate, histidine, lysine, threonine and tyrosine residues were particularly sensitive. Since hCP is a major copper transport protein, oxidative damage of hCP by SAL may induce perturbation of the copper transport system, which subsequently leads to deleterious conditions in cells. This study of the mechanism by which ceruloplasmin is modified by salsolinol may provide an explanation for the deterioration of organs under neurodegenerative disorders such as PD. [BMB Reports 2016; 49(1): 45-50]

• YAKHAK HOEJI
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• v.52 no.6
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• pp.488-493
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• 2008

2-Aminothiazole ring as a bioisoster of catechol in dopamine has provided with good oral availability and lipophilic property. 2-Aminoindan, is a rigid form of dopamine, was evaluated as a dopamine D3 agonist with low neurotoxicity. Dopamine D3 agonist was evaluated as selective for the treatment of Parkinson's disease. In order to develop a novel dopamine D3 agonist, we tried to synthesize the aminothiazoloindenoxazine derivative that is a hybrid structure of aminoindenoxazine and thiazole ring. cis-2-Amino-1-indanol (2) was synthesized from 1,2-indandione-2-oxime by catalytic hydrogenation and it was treated with chloroacetyl chloride and NaH in benzene solution to give (${\pm}$)-cis-4,4a,5,9b-tetrahydroindeno[1,2-b][1,4]oxazin-3(2H)-one (6). Nitration of 6 by the mixed acid gave 8-nitro compound (7) and the carbonyl group of 7 was reduced with $LiAlH_4$ to afford compound (8). 8 was reduced to form (${\pm}$)-cis-8-amino-2,3,4,4a,5,9b-hexahydroindeno[1,2-b][1,4]oxazine (9) and finally it was cyclized with KSCN in glacial acetic acid to yield (${\pm}$)-cis-8-amino-2,3,4,4a,5,10b-hexahydrothiazolo[4,5-f]indeno[1,2-b][1,4]oxazine (10).

• Archives of Pharmacal Research
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• v.14 no.4
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• pp.290-294
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• 1991

For the determination of peripheral COMT activity, we synthesized $[2-^{14}C]-3',4'-dihydroxyacetophenone([^{14}C]-DHAP)$, a model substrate closely related to catecholamines, which cannot be attacked by monoamine oxidase. After i.v.-injection of $[^{14}C]-DHAP$ in living animals, only 3',4'-dihydroxy-acetophenone (3',4'-DHAP) and 3'-methoxy-4'-hydroxyacetophenone (3'-MHAP) were detected in blood by thin layer radio chromatography. It could be speculated that 3',4'-DHAP was primarily O-methylated by COMT, followed by subsequent conjugations. The concentration of 3',4'-DHAP, a substrate for COMT, in blood at 5 min after injection of $[^{14}C]-DHAP$, were similar in all animals. The rate of 3'-MHAP formation can be therefore used as an indicator for peripheral COMT activity. The velocity of methylation in 15 min after i.v.-administration of $[^{14}C]-DHAP$ was $0.28\;{\mu}g/ml{\cdot}min$. From these results, 3',4'-DHAP was shown to be used as an appropriate substrate to determine the COMT activity in vivo.

• Journal of Microbiology
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• v.38 no.2
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• pp.53-61
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• 2000

Hydroxybenzoic acids are the most important intermediates in the degradative pathways of various aromatic compounds. Microorganisms catabolize aromatic compounds by converting them to hydroxylated intermediates and then cleave the benzene nucleus with ring dioxygenases. Hydroxylation of the benzene nucleus of an aromatic compound is an essential step for the initiation and subsequent disintegration of the benzene ring. The incorporation of two hydroxyl groups is essential for the labilization of the benzene nucleus. Monohydroxybenzoic acids such as 2-hydroxybenzoic acid, 3-hydroxybenzoic acid, and 4-hydrosybenzoic acid, opr pyrocattechuic acid that are susceptible for subsequent oxygenative cleavage of the benzene ring. These terminal aromatic intermediates are further degraded to cellular components through ortho-and/or meta-cleavage pathways and finally lead to the formation of constituents of the TCA cycle. Many groups of microorganisms have been isolated as degraders of hydroxybenzoic acids with diverse drgradative routes and specific enzymes involved in their metabolic pahtway. Various microorganisms carry out unusual non-oxidative decarboxylation of aromatic acids and convert them to respective phenols which have been documented. Futher, Pseudomonas and Bacillus spp. are the most ubiquitous microorganisms, being the principal components of microflora of most soil and water enviroments.

• Journal of Soil and Groundwater Environment
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• v.19 no.3
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• pp.47-55
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• 2014

Arthrobacter chlorophenolicus A6 possesses several monooxygenases (CphC-I, CphC-II, and CphB) that can catalyze the transformation of 4-chlorophenol (4-CP) to hydroxylated intermediates in the initial steps of substrate metabolism. The corresponding genes of the monooxygenases were cloned, and the competent cells were transformed with these recombinant plasmids. Although CphC-II and CphB were expressed as insoluble forms, CphC-I was successfully expressed as a soluble form and isolated by purification. The specific activity of the purified CphC-I was analyzed by using 4-CP, 4-chlorocatechol (4-CC), and catechol (CAT) as substrates. The specific activities for 4-CP, 4-CC, and CAT were determined to be 0.312 U/mg, 0.462 U/mg, 0.246 U/mg, respectively. The results of this study indicated that CphC-I is able to catalyze the degradation of 4-CC and CAT in addition to 4-CP, which is a primary substrate. This research is expected to provide the fundamental information for the development of an eco-friendly biochemical degradation of aromatic hydrocarbons.

• Bulletin of the Korean Chemical Society
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• v.18 no.6
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• pp.628-631
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• 1997

The preparation and characterization of $Co(dmppz)_2(3,6-dbq)_2$ (dmppz=1,4-dimethylpiperazine; 3,6-dbq=3,6-di-tert-butyl-1,2-quinone) are established. Temperature-dependent magnetic moments (100-400 K), variable-temperature IR, and electronic spectra are presented to show that the title complex exhibits an equilibrium via a catechol to cobalt intramolecular electron transfer. At temperatures below 350 K, the charge distribution of the complex is $Co^Ⅲ(dmppz)_2(3,6-dbsq)(3,6-dbcat)$ (3,6-dbsq=3,6-di-tert-butyl-1,2-semiquinonato; 3,6-dbcat=3,6-di-tert-butylcatecholato) whereas at the temperature beyond 390 K, the complex is predominantly Co^Ⅱ(dmppz)_2(3,6-dbsq)_2$ form in the solid state. At the temperature range of 350-390 K a mixture of Co(Ⅲ) and Co(Ⅱ) redox isomers exist at equilibrium. The transition temperature (Tc) of Co(Ⅲ)/Co(Ⅱ) in solution is approximately 50° lower than that in the solid state. In particular, thermal analysis on solid sample of the complex discloses that the transition for the Co(Ⅲ)/Co(Ⅱ) is accompanied by the change in heat content of 12.30 kcal/mol.

• Polymer(Korea)
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• v.38 no.1
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• pp.108-112
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• 2014

Novel adhesive polyaspartamides containing catechol and primary amine pendent groups were synthesized through successive ring-opening aminolysis reactions of dopamine (DOP) and ethylenediamine (EDA) with polysuccinimide (PSI). The oxidative gelation of aqueous dopamine-modified polyaspartamide was observed by adding $NaIO_4$ as the oxidizing reagent. FTIR, UV-vis and oscillatory rheometry was used to elucidate the oxidative cross-linking toward gel formation. The prepared gel was characterized by the swelling degree, thermogravimetric analysis (TGA), and by scanning electronic microscopy (SEM).

• Bulletin of the Korean Chemical Society
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• v.13 no.3
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• pp.230-235
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• 1992

The conformational analysis has been done for catecholamines (dopamine, norepinephrine, and epinephrine) in the cationic and di-anionic states. The species responsible for adsorption on silver metal surface is anionic deprotonated at hydroxyl groups of catechol moiety, i.e., di-anionic states of catecholamines. This was deduced from Fourier-transform Raman spectra of sodium salts of catecholamines. High resolution proton NMR (400 MHz) spectra of catecholamines in basic and neutral $D_2O$ solution show that the conformations of norepinephrine and epinephrine in the di-anionic states are preferred in gauche, but not for dopamine in the di-anionic state. However the energy difference between trans and gauche of catecholamines in the protonated cationic states is small enough to rotate freely through C-C bond in ethylamine moiety. The conformational calculations using an empirical potential function and the hydration shell model (a program CONBIO) show consistent with above experimental results. The calculations suggest that the species of catecholamines adsorbed on silver metal surface would be in favor of the gauche conformations.