• Title/Summary/Keyword: L-Proline

Search Result 328, Processing Time 0.049 seconds

Thermodynamic Parameters of Complexation of Lanthanides by L-proline (Lanthanides-L-proline 착물의 형성에 관한 열역학적 연구)

  • Choi Im-Yeon;Kim Young-Inn;Choi Sung-Nak;Hyun Myung-Ho
    • Journal of the Korean Chemical Society
    • /
    • v.37 no.1
    • /
    • pp.105-111
    • /
    • 1993
  • The stability constants for lanthanides complexes with optically active L-proline (1 : 1) were determined in aqueous solution in the ionic medium of 0.1 M $NaClO_4$ at 25$^{\circ}C$ using a pH titration method. The results show called "gadolinium break" between lighter and heavier lanthanides. The linear relation between the stability constant (log$\beta$1) and the pKa values of ligands indicates that L-proline acts as a bidentate ligand in the complexation. The thermodynamic parameters (${\Delta}H$ and ${\Delta}S$) were also determined using an enthalpy titration method at the same condition. The positive endothermic enthalpy change and positive entropy change clearly indicate that the driving force for the complexation is an entropy effect. The comparison of the thermodynamic parameters of L-proline complexes with anthranilate complexes supports the conclusion that the heterocyclic nitrogen atom and carboxylate of L-proline are involved in the chleate formation. The enthalpy values for L-proline are more positive than the ones for anthranilate complex. The difference in enthalpy change for the complex formation between L-proline complex and anthranilate complex is explained in terms of the basicity of the nitrogen donor atom in the ligand. The relatively large entropy change may be described by the extra dehydration related to the rigidity of L-proline ring.

  • PDF

연속배양을 통한 L-prolinc 발효공정의 최적화 연구

  • Yu, Ji-Myeong;Choe, Sun-Yong;Jang, Hyeong-Uk;An, Jeong-O;Jo, Yeong-Il;Lee, Hong-Won;Jeong, Jun-Gi
    • 한국생물공학회:학술대회논문집
    • /
    • 2001.11a
    • /
    • pp.426-429
    • /
    • 2001
  • The continuous production of L -proline was studied using L-histidine auxotrophic mutant of Corynebacterium acetoacidophilum under various substrate limited conditions. Among the $NH_4\;^+$ $PO_4\;^3$ and L -histidine limited conditions, the highest production of L -proline was observed under the L-histidine limited condition. Under $NH_4\;^+$ and $PO_4\;^3$ limited conditions, no or poor L-proline production was observed, respectively. For the kinetic parameters under L -histidine limitation the specific rate of L -proline production was increased with dilution rate upto $0.1hr^{-1}$ but decreased above $0.1hr^{-1}$. The volumetric rate of L -proline production was showed similar pattern with specific rate. The dried cell weight was gradually increased according to decrease the dilution rate. Specific rate of glucose consumption was proportionally increased with dilution rate. The results of continuous culture (higher production of L-proline at dilution rate $0.1hr^{-1}$) will be used in fed-batch culture for the control of cell growth rate and mass production of L-proline.

  • PDF

Isolation of a High-Yield Mutant Strain for L-Proline Production and Its Fermentation Conditions

  • Ryu, Wuk-Sang;Jang, Hyung-Wook;Cho, Kyoung-Hee;Chang, Soon-Jae;Ryu, Yeon-Woo;Park, Young-Hoon
    • Journal of Microbiology and Biotechnology
    • /
    • v.9 no.5
    • /
    • pp.613-618
    • /
    • 1999
  • L-Proline-producing mutant strains were developed by exposing L-glutamic acid-producing bacteria to N-metyl-N-nitro-nitrosoguanidine and UV irradiation. A L-histidine auxotroph of Corynebacterium acetoacidophilum RYU3161(KCTC 0616BP), which was resistant to sulfaguanidine and proline analogs (DHP, AZC, TAC), was isolated. The activity of the mutant strain's $\gamma$-glutamyl kinase was 45% higher than that of the parent strain. The optimum level of L-histidine for production of L-proline was 0.16 g/l. In a 5-1 jar fermenter, the mutant strain produced L-proline at a high concentration (35 g/l) level within 48 h of cultivation.

  • PDF

Effect of Growth Rate on the Production of L-Proline in the Fed-batch Culture of Corynebacterium acetoacidophilum

  • Ahn, Jung-Oh;Ryu, Jim-Yung;Jang, Hyung-Wook;Jung, Jun-Ki
    • Biotechnology and Bioprocess Engineering:BBE
    • /
    • v.9 no.4
    • /
    • pp.326-329
    • /
    • 2004
  • Corynebacterium acetoacidophilum RYU3161 was cultivated in a L-histidine-limited fed-batch culture. To investigate the effect of cell growth on the L-proline production, 5 L fed-batch culture was performed using an exponential feeding rate to obtain the specific growth rates $(\mu)$ of 0.04, 0.06, 0.08, and 0.1 $h_1$. The results show that the highest production of L-proline was obtained at $\mu$ = 0.04 $h_1$. The specific L-proline production rate $(Q_p)$ increased pro-portionally as a function of the specific growth rate, but decreased after it revealed the maxi-mum value at $\mu$ = 0.08 $h_1$. Thus, the highest productivity of L-proline was 1.66 g $L^-^1 h^-^1$ at $\mu$ = 0.08 $h_1$. The results show that the production of L-proline in C. acetoacidophilum RYU3161 has mixed growth-associated characteristics.

Optical Resolution of Free Amino Acids with Addition of Copper(II) Chelates in a Reversed-Phase Liquid Chromatography (구리(II) 킬레이트의 첨가에 의한 자유아미노산 광학이성질체의 역상 액체크로마토그래피적 분리)

  • Sun Haing Lee;Tae Sub Oh;Hong Yeup An;Kyung Sug Park;Sang Oh OH
    • Journal of the Korean Chemical Society
    • /
    • v.36 no.6
    • /
    • pp.879-888
    • /
    • 1992
  • Separation of the optical isomers of free amino acids by a reversed phase high performance liquid chromatography has been studied by adding a copper(II) complex of L-proline or L-proline derivatives (hydroxy-L-proline, N-benzyl-L-proline, p-xylenyl-L-proline, p-xylenyl-hydroxy-L-proline) in the mobile phase. An OPA postcolumn detection system was used for the detection of amino acids. The chromatographic properties for the free amino acids were discussed in terms of the pH, the kinds and concentration of chelate or organic modifier. The retention behaviors of the free amino acids were considerably different from, those of DNS-amino acids or DABS-amino acids. The enantioselectivity of the free amino acids was better than that of derivatized amino acids. The enantioselectivity between the optical isomers observed by use of the Cu(II)-p-xylenyl-L-proline chiral cheleate was the best among the several copper(II) chelate. A separation mechanism could be illustrated not only by the hydrophobic interaction of the diastereomer with stationary phase but also by the steric effect of the ligand exchange reaction between the free-amino acids and copper chelate.

  • PDF

Optical Resolution of Dansyl Amino acids by Xylenyl-L-proline Copper (Ⅱ) Complex (Xylenyl-L-proline 구리 (Ⅱ) 착물을 이용한 단실아미노산의 광학분리)

  • Lee, Seon Haeng;O, Dae Seop;Park, Bun Ja
    • Journal of the Korean Chemical Society
    • /
    • v.34 no.1
    • /
    • pp.76-84
    • /
    • 1990
  • Optical isomers of dansyl amino acids were separated by a chiral mobile phase addition method. Two metha and para isomers of xylenyl-L-proline were prepared and used as the ligands of copper(Ⅱ) chelate to resolve the dansyl amino acids. Their elution behaviors were similar to those obtained from the addition of copper (Ⅱ) benzyl-L-proline chelate. The matrix effect of the mobile phase such as pH, concentration of buffer and compositions of organic solvent acetonitrile affected the optical resolution. The separation mechanism could be explained by a cis-trans effect of the ligand exchange reaction and hydrophobic interaction between the ternary complex and the stationary phase.

  • PDF

Proline Analogs, L-Azetidine-2-Carboxylic Acid and 3,4-Dehydro-L-Proline, Induce Stress Response in Drosophila Kc Cells

  • Moon, Sung-Joon;Han, Ching-Tack
    • BMB Reports
    • /
    • v.31 no.2
    • /
    • pp.201-208
    • /
    • 1998
  • Amino acid analogs, like other inducers of stress response, induce the synthesis of stress proteins in mammalian cells. In this study, Drosophila Kc cells, in which translation is tightly controlled during stress response, was treated with proline analogs, L-azetidine-2-carboxylic acid (AzC) and 3,4-dehydro-L-proline (dh-P). Kc cells exposed to AzC or dh-P induced the synthesis of several proteins which had the same molecular weights as known heat shock proteins. However, in Kc cells, normal protein synthesis still continued in the presence of amino acids analogs unlike in heat-shocked cells. For the induction of stress response, the incorporation of dh-P into the protein was not essential, but the incorporation of AzC was. The stress protein synthesis was regulated mainly at the transcriptional level by AzC, whereas it was regulated by dh-P at the transcription level and possibly posttranscription level. During recovery, the stress protein synthesis stopped sooner in analog-treated cells than in heat-shocked cells even though the accumulated amount of Hsp70 was much less in proline analogstreated cells. It could be concluded that the proline analogs, AzC and dh-P, induced stress response through a different mechanism from heat shock.

  • PDF

Theoretical Insight into the Mechanism of an Efficient ʟ-Proline-catalyzed Transamidation of Acetamide with Benzylamine

  • Wu, Weirong
    • Bulletin of the Korean Chemical Society
    • /
    • v.35 no.9
    • /
    • pp.2673-2678
    • /
    • 2014
  • The detailed mechanisms of the efficient $\small{L}$-proline and pyrrolidine catalyzed transamidation of acetamide with benzylamine have been investigated using density functional theory (DFT) calculations. Our calculated results show: (1) the mechanisms of two catalytic cycle reactions are similar. However, the rate-determining steps of their reactions are different for the whole catalytic process. One is the intramolecular nucleophilic addition reaction of 1-COM, the other is hydrolysis reaction of 2-C. (2) COOH group of $\small{L}$-proline is essential for efficient transamidation. The computational results are in good agreement with the experiment finding and mechanism resported by Rao et al. for $\small{L}$-proline-catalyzed synthesis of amidesin good to excellent yields.

Modeling and Measurements of the Activity Coefficients and Solubilities of Amino Acids in the L-valine/electrolyte and L-proline/electrolyte Aqueous Solutions (L-Valine/전해질 및 L-Proline/전해질 수용액에서 아미노산의 활동도계수와 용해도의 측정 및 모델링)

  • Lee, Bong-Seop;Kim, Ki-Chang
    • Korean Chemical Engineering Research
    • /
    • v.50 no.1
    • /
    • pp.93-105
    • /
    • 2012
  • Activity coefficients and solubilities of L-Valine and L-Proline in aqueous solutions containing each of four electrolytes such as NaCl, KCl, $NaNO_3$ and $KNO_3$ were measured at 298.15 K. The measurements of activity coefficients were carried out in the electrochemical cell coupled with two ion-selective electrodes (cation and anion), and the solubilities were measured by the gravimetric analysis of saturated solutions in equilibrium with the solid phase of amino acid. The measured activity coefficients of electrolytes and amino acids were correlated with the theoretical thermodynamic model presented in the previous work [Korean Chem. Eng. Res. 48(4), 519(2010)]. It was found that the activity coefficients of amino acids and electrolytes described based on the our previous model were well agreeable with experimental data. Also the experimental solubility data of L-Valine and L-Proline were successfully correlated with the thermodynamic relation mentioned in the previous work.