• Journal of Microbiology and Biotechnology
• /
• v.5 no.6
• /
• pp.315-318
• /
• 1995

Sulfanilic acid (4-aminobenzenesulfonic acid) alone is normally not permeant in bacteria but can be readily delivered via the microbial dipeptide transport system. A dipeptidyl derivative of this compound, L-phenylalanyl-L-2-sulfanilylglycine (PSG), prepared by attachment of its primary amino group to the phenylalanyl $\alpha$-glycine moiety, appeared to have a Km of 0.125 mM and a Vmax of 1.9 nmoles/ml/min ($A_{660}$, 1.0) in Escherichia coli. From competitive spectrophotometric analysis, it was found that the type of amino acids in both of the N- and C-terminals affected the kinetic power of dipeptides. The growth inhibitory effect of PSG was over 7 times more potent than that of the sulfanilic acid against E. coli, suggesting that this potential inhibition was presumably due to the increased hydrophobic nature of the sulfanilyl dipeptide.

• Journal of the Korean Chemical Society
• /
• v.53 no.2
• /
• pp.137-143
• /
• 2009

Liquid chromatographic enantiomer separation of N-tert-butoxycarbonyl (BOC) $\alpha$-amino acids and their ethyl esters was performed on covalently immobilized chiral column (Chiralpak IC) derived from polysaccharide derivative. The solvent versatility of the covalently immobilized Chiralpak IC in enantiomer separation of N-BOC $\alpha$-amino acid ethyl ester derivatives was shown and the chromatographic parameters of their enantioselectivities and resolution factors were greatly influenced by the nature of the mobile phase. Also the effect on the dissolving solvent for these analytes on the enantiomer separation using the same mobile phase and the examples of preparative enantiomer separation on analytical column were shown.

• Applied Chemistry for Engineering
• /
• v.4 no.2
• /
• pp.254-263
• /
• 1993

The industry of amino acids has developed for the synthetic methods, zymotechnics from the methods of extraction. In the present, part of amino acids (L-cystine, L-tyrosine, etc.) is manufactured by the methods of extraction, but most of amino acids is produced by synthetic methods, zymotechnics. Among the methods, the synthetic methods use of cyanic acid, which generate a large of waste water by acid or alkali in hydrolysis. In this point of view, improved new synthetic methods are demanded for being the influence of environment. This article Introduces new synthetic methods of phenyl alnine, further more, the recent of research results are introduced to prepare the derivative ${\alpha}-keto$ acids of precursor for preparing more than particular amino acids.

• Journal of Life Science
• /
• v.9 no.1
• /
• pp.63-68
• /
• 1999

Many nucleoside compounds such as 5-halogen substituted uridine, 5'-amino-5'-deoxyuridine conjugates of amino acid, peptide, and penicillin G, 5'-monophosphate uridine derivatives and 5'-monophosphate uridine-fatty acid derivatives were chemically synthesized and their antifungal, antibacterial, and antitumor activities were tested. 5-Bromo-2',3'-O-isopropylideneuridine(6) inhibited the growth of Trichophyton rubrum at $0.2{\mu}$g/ml of MIC. 5'-Amino-5'-deoxyuridine-penicillin G(19), 5'-amino-5'-deoxyuridine-cyclo(Phe-Asp)(20), and 5-iodo-5'-amino-5'-deoxyuridine- penicillin G(22) had antibarterial activity(MIC was $6.25{\mu}$g/ml against S. aureus) and the latter two nucleoside compounds were the most antitumor derivatives(their $IC_{50}$ against L5178Y murine lymphoma cell was $6.5{\mu}$g/ml).

• YAKHAK HOEJI
• /
• v.44 no.3
• /
• pp.279-282
• /
• 2000

The inhibition mode of S-hydroxy-2-phenylalanylaminomethyl-4-pyron ($IC_{50}=24.6{\;}{\mu}M$) on mushroom tyrosinase was investigated using L-tyrosine as a substrate. This inhibitor is the kojic acid derivative, where the C-7 hydroxyl of kojic acid was replaced by amino group and coupled to the carboxyl of L-phenylalanine. The kinetic data obtained show a competitive inhibition pattern.

• Journal of the Korean Electrochemical Society
• /
• v.7 no.2
• /
• pp.83-88
• /
• 2004

[ $DeniLite^{TM}$ ] laccase immobilized Pt electrode was used for amperometric detection of some catechol derivatives and o-aminophenol (OAP) derivative by means of substrate recycling. In case of catechol derivatives, the obtained sensitivities are 85, 79 and $57 nA/{\mu}M$ with linear ranges of $0.6\~30,\;0.6\~30\;and\; 1\~25 {\mu}M$ and detection limits (S/N=3) of 0.2, 0.2 and $0.3{\mu}M$ for 3,4-dihydroxycinnaminic acid (3,4-DHCA), 3,4-dihydroxybenzoic acid (3,4-DHBA) and 3,4-dihydroxyphenylacetic acid (3,4-DHPAA), respectively. In case of OAP derivative, the obtained sensitivity is $237 nA/{\mu}M$ with linear range of $0.2\~15{\mu}M$ and detection limit of 70 nM for 2-amino-4-chlorophenol (2-A-4-CP). The response time $(t_{90\%})$ is about 2 seconds for each substrate and the long-term stability is around 40-50days for catechol derivatives and 30 days for 2-A-4-CP with retaining $80\%$ of initial activity. The optimal pHs of the sensor for these substrates are in the range of 4.5-5.0, which indicates that stability of the enzymatically oxidized product plays a very important role in substrate recycling. The different sensitivity of the sensor for each substrate can be explained by the electronic effect of the sugstituent on the enzymatically oxidized form.

• Journal of Microbiology and Biotechnology
• /
• v.16 no.9
• /
• pp.1477-1480
• /
• 2006

The 63-amino-acid-encoding afsR2 is a global antibiotics-stimulating regulatory gene identified from the chromosome of Streptomyces lividans. To dissect a putative functional domain in afsR2, several afsR2-derivative deletion constructs were generated and screened for the loss of actinorhodin-stimulating capability. The afsR2-derivative construct missing a 50-bp C-terminal region significantly lost its actinorhodin-stimulating capability in S. lividans. In addition, site-directed mutagenesis on amino acid positions of #57-#61 in a 50-bp C-terminal region, some of which are conserved among known Sigma 70 family proteins, significantly changed the AfsR2's activity. These results imply that the C-terminal region of AfsR2 is functionally important for antibiotics-stimulating capability and the regulatory mechanism might be somehow related to the sigma-like domain present in the C-terminal of AfsR2.

• Applied Biological Chemistry
• /
• v.35 no.2
• /
• pp.132-138
• /
• 1992

For effective determination of methylthiohydantoin amino acids(MTHs) by gas liquid chromatography in the protein sequencing, derivatization with N-methyl-N-(tert.-butyl-dimethylsilyl)trifluoroacetamide(MTBSTFA), a new silylating reagents, was attempted instead of trimethylsilyl(TMSi) derivatives by N,O-bis(trimethylsilyl)trifluoroacetamide(BSTFA) used up to the present and N(O)-butyldimethylsilyl MTHs derivatized by MTBSTFA were analysed on HP-1 capillary column. Twenty one protein amino acids except cystine were indentified. Especially arginine that did not detected with TMSi derivative on packed column until now was resolved by derivatization with MTBSTFA. N(O)-butyldimethylsilyl MTHs showed multiple peaks by MTBSTFA were proline, isoleucine, glycine and tyrosine and hydroxyproline especially showed several extraneous peaks more than two. Calibration curves of N(O)-butyldimethysilyl MTHs of amino acids in the range of $2.5\;nmol{\sim}7.5\;nmole$ showed good linearity. however, those of lysine, histidine and arginine showed linearity in the range of $5.0\;nmole{\sim}15.0\;nmole$. Correlation coefficients and regression coefficients of all calibration curves were highly significant(p<0.001).

• Archives of Pharmacal Research
• /
• v.20 no.2
• /
• pp.184-190
• /
• 1997

A new method based on the chemical reaction has been devised for the sequential analysis of reducing oligosaccharides using 8-amino-2-naphthalenesulfonic acid (ANS), a fluorescent precolumn derivatization reagent for reducing saccharides. The procedure established includes 1) the derivatization of a reducing oligosaccharide to produce a Schiff base, 2) the reduction of the base with sodium cyanoborohydride $(NaBH_3/CN), 3)$ the methoxycarbonylation of the resultant secondary amino group, 4) the cleavage of the glycoside bond next to the reducing end, based on the intramolecular acid hydrolysis by the action of a sulfonic acid group of the ANS derivative, 5) the identification of the liberated reducing end by high-performance liquid chromatography (HPLC), and finally 6) the recovery of the resultant oligosaccharide fragment from the cleavage reaction mixture. The extensive examination of the conditions for the sequential analysis of reducing oligosaccharides resulted in the procedure of simplicity , high selectivity and high recovery. This procedure was found to be useful for the sequential analysis of di-, tri- and tetrasaccharides.

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