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Aihua Zou - One of the best experts on this subject based on the ideXlab platform.

  • hydrotrope and hydrotrope solubilization action of Penicillin K in ctab n c5h11oh h2o system
    Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2002
    Co-Authors: Rong Guo, Qiqing Zhang, Junhong Qian, Aihua Zou
    Abstract:

    Abstract Penicillin potassium salt (Penicillin-K) is found to show hydrotrope action, which can increase the solubility of cationic surfactant CTAB in water. Penicillin-K also shows hydrotrope-solubilization action, which maKes the W/O and O/W microemulsion more stable and increases the solubilized amount of n-C5H11OH in O/W microemulsion and that of water in W/O microemulsion for CTAB/n-C5H11OH/H2O system. However, in this system, the presence of Penicillin-K can decrease the stability of the lamellar liquid crystal phase due to its structure change to bicontinuous, which are proved by the mechanism of its hydrotrope-solubilization action.

  • Hydrotrope and hydrotrope-solubilization action of Penicillin-K in CTAB/n-C5H11OH/H2O system
    Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2002
    Co-Authors: Rong Guo, Qiqing Zhang, Junhong Qian, Aihua Zou
    Abstract:

    Abstract Penicillin potassium salt (Penicillin-K) is found to show hydrotrope action, which can increase the solubility of cationic surfactant CTAB in water. Penicillin-K also shows hydrotrope-solubilization action, which maKes the W/O and O/W microemulsion more stable and increases the solubilized amount of n-C5H11OH in O/W microemulsion and that of water in W/O microemulsion for CTAB/n-C5H11OH/H2O system. However, in this system, the presence of Penicillin-K can decrease the stability of the lamellar liquid crystal phase due to its structure change to bicontinuous, which are proved by the mechanism of its hydrotrope-solubilization action.

Rong Guo - One of the best experts on this subject based on the ideXlab platform.

  • hydrotrope and hydrotrope solubilization action of Penicillin K in ctab n c5h11oh h2o system
    Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2002
    Co-Authors: Rong Guo, Qiqing Zhang, Junhong Qian, Aihua Zou
    Abstract:

    Abstract Penicillin potassium salt (Penicillin-K) is found to show hydrotrope action, which can increase the solubility of cationic surfactant CTAB in water. Penicillin-K also shows hydrotrope-solubilization action, which maKes the W/O and O/W microemulsion more stable and increases the solubilized amount of n-C5H11OH in O/W microemulsion and that of water in W/O microemulsion for CTAB/n-C5H11OH/H2O system. However, in this system, the presence of Penicillin-K can decrease the stability of the lamellar liquid crystal phase due to its structure change to bicontinuous, which are proved by the mechanism of its hydrotrope-solubilization action.

  • Hydrotrope and hydrotrope-solubilization action of Penicillin-K in CTAB/n-C5H11OH/H2O system
    Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2002
    Co-Authors: Rong Guo, Qiqing Zhang, Junhong Qian, Aihua Zou
    Abstract:

    Abstract Penicillin potassium salt (Penicillin-K) is found to show hydrotrope action, which can increase the solubility of cationic surfactant CTAB in water. Penicillin-K also shows hydrotrope-solubilization action, which maKes the W/O and O/W microemulsion more stable and increases the solubilized amount of n-C5H11OH in O/W microemulsion and that of water in W/O microemulsion for CTAB/n-C5H11OH/H2O system. However, in this system, the presence of Penicillin-K can decrease the stability of the lamellar liquid crystal phase due to its structure change to bicontinuous, which are proved by the mechanism of its hydrotrope-solubilization action.

Junhong Qian - One of the best experts on this subject based on the ideXlab platform.

  • hydrotrope and hydrotrope solubilization action of Penicillin K in ctab n c5h11oh h2o system
    Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2002
    Co-Authors: Rong Guo, Qiqing Zhang, Junhong Qian, Aihua Zou
    Abstract:

    Abstract Penicillin potassium salt (Penicillin-K) is found to show hydrotrope action, which can increase the solubility of cationic surfactant CTAB in water. Penicillin-K also shows hydrotrope-solubilization action, which maKes the W/O and O/W microemulsion more stable and increases the solubilized amount of n-C5H11OH in O/W microemulsion and that of water in W/O microemulsion for CTAB/n-C5H11OH/H2O system. However, in this system, the presence of Penicillin-K can decrease the stability of the lamellar liquid crystal phase due to its structure change to bicontinuous, which are proved by the mechanism of its hydrotrope-solubilization action.

  • Hydrotrope and hydrotrope-solubilization action of Penicillin-K in CTAB/n-C5H11OH/H2O system
    Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2002
    Co-Authors: Rong Guo, Qiqing Zhang, Junhong Qian, Aihua Zou
    Abstract:

    Abstract Penicillin potassium salt (Penicillin-K) is found to show hydrotrope action, which can increase the solubility of cationic surfactant CTAB in water. Penicillin-K also shows hydrotrope-solubilization action, which maKes the W/O and O/W microemulsion more stable and increases the solubilized amount of n-C5H11OH in O/W microemulsion and that of water in W/O microemulsion for CTAB/n-C5H11OH/H2O system. However, in this system, the presence of Penicillin-K can decrease the stability of the lamellar liquid crystal phase due to its structure change to bicontinuous, which are proved by the mechanism of its hydrotrope-solubilization action.

Qiqing Zhang - One of the best experts on this subject based on the ideXlab platform.

  • hydrotrope and hydrotrope solubilization action of Penicillin K in ctab n c5h11oh h2o system
    Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2002
    Co-Authors: Rong Guo, Qiqing Zhang, Junhong Qian, Aihua Zou
    Abstract:

    Abstract Penicillin potassium salt (Penicillin-K) is found to show hydrotrope action, which can increase the solubility of cationic surfactant CTAB in water. Penicillin-K also shows hydrotrope-solubilization action, which maKes the W/O and O/W microemulsion more stable and increases the solubilized amount of n-C5H11OH in O/W microemulsion and that of water in W/O microemulsion for CTAB/n-C5H11OH/H2O system. However, in this system, the presence of Penicillin-K can decrease the stability of the lamellar liquid crystal phase due to its structure change to bicontinuous, which are proved by the mechanism of its hydrotrope-solubilization action.

  • Hydrotrope and hydrotrope-solubilization action of Penicillin-K in CTAB/n-C5H11OH/H2O system
    Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2002
    Co-Authors: Rong Guo, Qiqing Zhang, Junhong Qian, Aihua Zou
    Abstract:

    Abstract Penicillin potassium salt (Penicillin-K) is found to show hydrotrope action, which can increase the solubility of cationic surfactant CTAB in water. Penicillin-K also shows hydrotrope-solubilization action, which maKes the W/O and O/W microemulsion more stable and increases the solubilized amount of n-C5H11OH in O/W microemulsion and that of water in W/O microemulsion for CTAB/n-C5H11OH/H2O system. However, in this system, the presence of Penicillin-K can decrease the stability of the lamellar liquid crystal phase due to its structure change to bicontinuous, which are proved by the mechanism of its hydrotrope-solubilization action.

Carmen Acebal - One of the best experts on this subject based on the ideXlab platform.

  • Newly Discovered Penicillin Acylase Activity of Aculeacin A Acylase from Actinoplanes utahensis
    Applied and environmental microbiology, 2007
    Co-Authors: Jesús Torres-bacete, Miguel Arroyo, Carmen Acebal, Daniel Hormigo, Maribel Stuart, Pedro Torres, M. P. Castillon, José Luis García, Isabel De La Mata
    Abstract:

    Aculeacin A acylase from Actinoplanes utahensis produced by Streptomyces lividans revealed acylase activities that are able to hydrolyze Penicillin V and several natural aliphatic Penicillins. Penicillin K was the best substrate, showing a catalytic efficiency of 34.79 mM(-1) s(-1). Furthermore, aculeacin A acylase was highly thermostable, with a midpoint transition temperature of 81.5 degrees C.

  • Optimization of culture medium and conditions for Penicillin acylase production by streptomyces lavendulae ATCC 13664
    Applied Biochemistry and Biotechnology, 2005
    Co-Authors: Jesús Torres-bacete, Miguel Arroyo, Raquel Torres-guzmán, Isabel De La Mata, Carmen Acebal, M. Pilar Castillón
    Abstract:

    The culture medium for Streptomyces lavendulae ATCC 13664 was optimized on a shaKe-flasK scale by using a statistical factorial design for enhanced production of Penicillin acylalse. This extracellularenzyme recently has been reported to bea Penicillin Kacylase, presenting also high hydrolytic activity against Penicillin V and other natural aliphatic Penicillins such as Penicillin K, Penicillin F, and Penicillin dihydroF,. The factorial design indicated that the main factors that positively affect Penicillin acylase production by S. lavendulae were the concentration of yeast extract and the presence of oligoelements in the fermentation medium, whereas the presence of olive oil in the medium had no effect on enzyme production. An initial concentration of 2.5% (w/v) yeast extract and 3 μg/mL of CuSO_4·5H_2O was found to be best for acylase production. In such optimized culture medium, fermentation, of the microorganism yielded 289 IU/L of enzyme in 72 h when employing a volume medium/volume flasK ratio of 0.4 and a 300-rpm shaKing speed. The presence of copper, alone and in combination with other metals, stimulated biomass as well as Penicillin acylase production. The time course of Penicillin acylase production was also studied in the optimized medium and conditions. Enzyme production showed catabolite repression by different carbon sources such as glucose, lactose, citrate, glycerol, and glycine.

  • Chromogenic analogues of Penicillin dihydroF and Penicillin K for the continuous spectrophotometric determination of aliphatic Penicillin acylase activity
    Biotechnology Letters, 2002
    Co-Authors: Miguel Arroyo, Raquel Torres-guzmán, Jesús Torres-bacete, Isabel De La Mata, María Pilar Castillón, Carmen Acebal
    Abstract:

    The synthesis of 2-nitro-5-[(hexanoyl)-amino]-benzoic acid and 2-nitro-5-[(octanoyl)-amino]-benzoic acid as chromogenic substrates for the determination of aliphatic Penicillin acylase activity is described. During enzymatic hydrolysis, the released chromophore, 2-nitro-5-amino-benzoic acid, was detected at 405 nm. Penicillin acylase from Streptomyces lavendulae had an appreciable activity towards these substrates, which can then be used to detect Penicillin acylases able to cleave hexanoyl and octanoyl residues off synthetic amides as well as Penicillin dihydroF and Penicillin K, their natural analogues.

  • Substrate specificity of Penicillin acylase from Streptomyces lavendulae.
    Biochemical and biophysical research communications, 2002
    Co-Authors: Raquel Torres-guzmán, Miguel Arroyo, Jesús Torres-bacete, Isabel De La Mata, M. P. Castillon, Carmen Acebal
    Abstract:

    Abstract The Kinetic parameters of several substrates of Penicillin acylase from Streptomyces lavendulae have been determined. The enzyme hydrolyses phenoxymethyl Penicillin (Penicillin V) and other Penicillins with aliphatic acyl-chains such as Penicillin F, dihydroF, and K. The best substrate was Penicillin K (octanoyl Penicillin) with a Kcat/Km of 165.3 mM−1 s−1. The enzyme hydrolyses also chromogenic substrates as NIPOAB (2-nitro-5-phenoxyacetamido benzoic acid), NIHAB (2-nitro-5-hexanoylamido benzoic acid) or NIOAB (2-nitro-5-octanoylamido benzoic acid), however failed to hydrolyse phenylacetil Penicillin (Penicillin G) or NIPAB (2-nitro-5-phenylacetamido benzoic acid) and Penicillins with polar substituents in the acyl moiety. These results suggest that the structure of the acyl moiety of the substrate is more determinant than the amino moiety for enzyme specificity. The enzyme was inhibited by several organic acids and the extent of inhibition changed with the hydrophobicity of the acid. The best inhibitor was octanoic acid with a Ki of 0.8 mM. All the results, taKing together, point to an active site highly hydrophobic for this Penicillin acylase from Streptomyces lavendulae.