• Bulletin of the Korean Chemical Society
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• 제22권6호
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• pp.551-552
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• 2001

• Archives of Pharmacal Research
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• 제9권1호
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• pp.45-47
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• 1986

Phenylglycine was obtained as the sole metabolite when .alpha.-aminophenylacetonitrile was ted to the culture broth of Aspergillus furmigatus furmigatus. The isolated phenylglycine showed L-configuration with 80% optical purity. Examination of the hydrolysis of the substrate to phenylglycine with cell free extracts, and the supernatant fraction and the particulate fraction both of which were obtained after ultracentrifugation of the cell free extract at 100,000g, indicated that the nitrile group hydrolyzing enzymes, nitrilase existed not only in cytoplasm, but in microsome fractions.

• Journal of Microbiology and Biotechnology
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• 제11권2호
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• pp.329-332
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• 2001

It has been known that, in enzymatic synthesis of cephalexin, the conversion yield was reduced by high loading of ampicillin acylase. In order to elucidate this phenomena, pH-controlled synthesis of cephalexin was examined using a purified Acetobacter turbidans acylase. When the pH of the reaction mixture was maintained at $6.20{\pm}0.04$, the reduction of the maximal conversion rate was not observed even with high enzyme loading. The kinetic parameters also suggest that pH drop during the enzymatic synthesis of cephalexin was mainly attributed to the rapid hydrolysis of D-${\alpha}$-phenylglycine methyl ester to D-${\alpha}$-phenylglycine, rather than the disappearance of 7-amino-3-deacetoxycephalosporanic acid for cephalexin synthesis. At higher molar ratio of two substrates, [D-${\alpha}$-phenylglycine methyl ester]/[7-amino-3-deacetoxycephalosporanic acid], the conversion rate was also elevated under pH-controlled enzymatic synthesis, which implies that the main reason for the pH drop is due to the production of D-${\alpha}$-phenylglycine methyl easter, the effect of a water-methanol cosolvent system on the ester, the effect of a water-methanol cosolvent system on the conversion profile was also examined. Even the though the conversion rate was increased in 10% methanol solution, a higher than 16% methanol in the reaction mixture caused an inactivation of enzyme.

• Bulletin of the Korean Chemical Society
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• 제4권2호
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• pp.72-76
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• 1983

Cephaloglycin was synthesized directly from D-${\alpha}$ -phenylglycine methyl ester and 7-aminocephalosporanic acid using whole cell enzyme of Xanthomonas citri (IFO 3835). Some optimal conditions for cephaloglycin synthesis were investigated, and yield improvements for its production by several methods were attempted. Using the whole cell enzyme system, the reaction kinetic model for cephaloglycin synthesis is proposed, and the kinetic constants for D-${\alpha}$ -phenylglycine methyl ester hydrolysis, cephaloglycin synthesis, and cephaloglycin hydrolysis were determined. The $K_m$ values of D-${\alpha}$-phenylglycine methyl ester, 7-aminocephalosporanic acid, and cephaloglycin were 11 mM, 24 mM, and 167 mM, and $K_i$ value of D-${\alpha}$-phenylglycine was 15 mM, respectively. The pattern of product inhibition was found to be competitive one.

• Bulletin of the Korean Chemical Society
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• 제23권9호
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• pp.1291-1294
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• 2002

Various racemic N-protected ${\alpha}-amino$ acids such as N-t-BOC-(tert-butoxycarbonyl), N-CBZ-(benzyloxycarbonyl) and N-FMOC-(9-fluorenylmethyloxycarbonyl) ${\alpha}-amino$ acids were resolved as their anilide and 3,5-dimethylanilde derivatives on an HPLC chira l stationary phase (CSP) developed by modifying a commercial (S)-leucine CSP. The chromatographic resolution results were compared to those on the commercial (S)-leucine CSP. The resolutions were greater on the modified CSP than those on the commercial CSP with only one exception, the resolution of N-t-BOC-phenylglycine anilide. In addition, the chromatographic resolution behaviors were quite consistent except for the resolution of N-protected phenylglycine derivatives, the (S)-enantiomers being retained longer. Based on the chromatographic resolution behaviors and with the aid of CPK molecular model studies, we proposed a chiral recognition mechanism for the resolution of N-protected ${\alpha}-amino$ acid derivatives. However, for the resolution of N-protected phenylglycine derivatives, a second chiral recognition mechanism, which competes in the opposite sense with the first chiral recognition mechanism, was proposed. The two competing chiral recognition mechanisms were successfully used in the rationalization of the chromatographic behaviors for the resolution of N-protected phenylglycine derivatives.

• 대한화학회지
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• 제20권3호
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• pp.229-235
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• 1976

페닐아세트산을 이황화탄소와 사염화탄소 용매에서 광염소화시켜 $43{\%}$ 수득률로 ${\alpha}$-클로로페닐아세트산을 얻었다. 여기에 암모니아를 가하여 가열해 주었더니 $16\sim27{\%}$수득률로 페닐글리신이 합성되었다. 또한 글리신유도체에 광페닐화 반응을 아세톤, 벤조페논 증감제와 benzoylperoxide를 써서 시도하였다.

• Archives of Pharmacal Research
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• 제11권4호
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• pp.285-291
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• 1988

2-mercaptoethanol, thioglycolic acid, glutathione, 3-mercapto-1, 2-propanediol and 3-mercapto-2-butanol showed catalytic activities on the hydrolysis of $\alpha$-amino-phenylacetonitrile to phenylglycineamide at the rate of 12.19 $\times$ $10^{-2}$, 8.03 $\times$ $10^[-2}$, 6.83 $\times$ $10^{-2}$, 8.60 $\times$ $10^{-2}$ and 6.04 $\times$ $10^{-2}$ mM $min^{-1}$, respectively. hte hydrolysis rate was faster in buffer than in water. The hydrolysis of the nitrile compound to phenylglycine was limited.

• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 1986년도 추계학술대회
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• pp.525.2-525
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• 1986

Cephalexin synthesizing enzyme (${\alpha}$ amino acid ester hydrolase) was partially purified from the culture broth of Acetobacter turbidans ATCC9325 through ammonium sulfate fractionation, DEAE, CM, and Sephacryl S-200 gel filtration. The enzyme has optimum pH 6.0 and temperature, 40$^{\circ}C$ respectively. From the analysis of reaction mixtures by thin layer chromatographic and high performance liquid chromatographic techniques, it was confirmed this enzyme catalyzed simultaneously the following reactions : 1) Synthesis of cephalexin from D-${\alpha}$-phenylglycine methylester (PGM) and 7-amino 3-deacetoxy-cetoxycephalosporanic acid (7-ADCA) 2) Hydrolysis of cephalexin to form 7-ADCA and phenylglycine (PG) 3) Hydrolysis of PGM to form PG and methanol. Base on the above experimental observations, the reaction model of this enzyme was identical with that of the enzyme from Xanthomonas citri.

• Archives of Pharmacal Research
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• 제23권6호
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• pp.574-578
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• 2000

Protected $\alpha$-Phenyl glycine 17 and phenylalanine 18 and 19 have been synthesized through an efficient three-step sequence from the corresponding allyl ethers 5, 7, and 10. The key intermediate in this synthesis is the corresponding allylic amines prepared by reaction of allyl ethers with chlorosulfonyl isocyanate.

• Journal of Microbiology and Biotechnology
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• 제24권5호
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• pp.597-604
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• 2014

$\small{D}$-Phenylglycine aminotransferase ($\small{D}$-PhgAT) from Pseudomonas stutzeri ST-201 is useful for enzymatic synthesis of enantiomerically pure $\small{D}$-phenylglycine. However, its low protein solubility prevents its application at high substrate concentration. With an aim to increase the protein solubility, the N-terminus of $\small{D}$-PhgAT was genetically fused with short peptides ($A_1$ ${\alpha}$-helix, $A_2$ ${\alpha}$-helix, and ALAL, which is a hybrid of $A_1$ and $A_2$) from a ferredoxin enzyme of a halophilic archaeon, Halobacterium salinarum. The fused enzymes $A_1$-$\small{D}$-PhgAT, $A_2$-$\small{D}$-PhgAT, and ALAL-$\small{D}$-PhgAT displayed a reduced pI and increased in solubility by 6.1-, 5.3-, and 8.1- fold in TEMP (pH 7.6) storage, respectively, and 5-, 4.5-, and 5.9-fold in CAPSO (pH 9.5) reaction buffers, respectively, compared with the wild-type enzyme (WT-$\small{D}$-PhgAT). In addition, all the fused $\small{D}$-PhgAT displayed higher enzymatic reaction rates than the WT-DPhgAT at all concentrations of L-glutamate monosodium salt used. The highest rate, $23.82{\pm}1.47$ mM/h, was that obtained from having ALAL-$\small{D}$-PhgAT reacted with 1,500 mM of the substrate. Moreover, the halophilic fusion significantly increased the tolerance of $\small{D}$-PhgAT in the presence of NaCl and KCl, being slightly in favor of KCl, where under the same condition at 3.5 M NaCl or KCl all halophilic-fused variants showed higher activity than WT-$\small{D}$-PhgAT.