Heat inactivation of lipase from psychrotrophic Pseudomonas fluorescens P38: Activation parameters and enzyme stability at low or ultra-high temperatures

Owusu, Richard K.; Makhzoum, Abdullah; Knapp, J. S.

doi:10.1016/0308-8146(92)90048-7

Cited by 66 publications

(35 citation statements)

References 22 publications

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“…Kinetic stability indices (⌬G*, ⌬H*, ⌬S*) will be expected to be indicative of enzyme conformational stability with respect to some irreversible inactivation processes. 41 Significant changes of the ⌬G* values, the apparent Gibbs free energy for irreversible inactivation of enzymes, after invertase immobilization were not observed (Table I). Because ⌬G* values are often considered a poor measure of enzyme tertiary structure stability, other kinetic stability indices, for example, ⌬H* and ⌬S*, are likely to be a function for enzyme unfolding.…”

mentioning

confidence: 69%

Lactam–amide graft copolymers as novel support for enzyme immobilization

Queiroz

Vargas

Higa

et al. 2002

J of Applied Polymer Sci

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A graft random copolymer of N-vinyl-2-pyrrolidone and N,NЈ-dimethylacrylamide onto polypropylene was synthesized using a simultaneous gamma radiation technique from a 60 Co source, so that the hydrogel poly(propylene-g-vinylpyrrolidone-, thus produced by grafting, could be used as a support for enzyme immobilization. The grafted spheres showed very good swelling behavior in water due to the incorporation of hydrophilicity in the PP spheres. The influence of pH and temperature on as well as the determination of the kinetic parameters, K M and V max , for both immobilized and soluble invertase were determined. PP-g-(VP-co-DMAM) grafting onto the PP spheres caused a significant change in the water content of the support and was more pronounced for the spheres with a high degree of grafting. A porous structure of the polymeric spheres was observed by scanning electron microscopy (SEM). The porous structure contributed to the reaction rate decrease due to diffusional effects, as shown by the larger K M value observed for immobilized invertase relative to the free enzyme. The enzyme affinity for the substrate (K M /V max ) remains quite good after immobilization. The thermal stability of immobilized invertase was significatively higher than that of the free enzyme and a displacement of 20°C was observed for the immobilized enzyme.

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mentioning

confidence: 69%

Lactam–amide graft copolymers as novel support for enzyme immobilization

Queiroz

Vargas

Higa

et al. 2002

J of Applied Polymer Sci

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“…By using the conventional thermodynamic relations (Owusu, Makhzoum, 1992), the thermodynamic parameters related to the reaction catalyzed by XR and carried out at 303K were estimated (Table III). As can be concluded from Table III, the main thermodynamic parameters related to XR catalysis did not depend on the purity degree of the enzyme.…”

Section: Resultsmentioning

confidence: 99%

“…7), it was possible to estimate the activation energy of heat denaturation (E a ') for XR in the CH and APII. Furthermore, it was also possible to calculate the correspondent thermodynamic parameters related to the heat denaturation (ΔG', ΔH' and ΔS') as proposed by Owusu and Makhzoum (1992). All the values calculated were shown in Table III.…”

Section: Resultsmentioning

confidence: 99%

“…According to Owusu and Makhzoum (1992) values of ΔH' between 200 and 300 kJ/mol should indicate the thermal denaturation of protein by unfolding its tertiary and/or quaternary structure. Thereby, the ΔH' of 292 kJ/mol calculated for XR in APII (Table III) Table III it is also notorious that the variation of heat denaturation entropy for XR in APII was 3.6 times higher than XR in CH.…”

Section: Resultsmentioning

confidence: 99%

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Characterization of xylose reductase extracted by CTAB-reversed micelles from Candida guilliermondii homogenate

Cortez

Pessoa

Felipe³

et al. 2006

Rev. Bras. Cienc. Farm.

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“…Negative values of activation entropy of enzymatic reaction (ΔS*) are also reported in Table 1. They signify that the activation of enzymatic reaction is supported by entropy and the thermal deactivation did not entail any signifi cant changes in the secondary and tertiary structure of the enzyme (49). Negative values of ΔS* are probably due to the compaction of the enzyme molecule and such changes can occur from the formation charge of neighbourhood molecules of enzyme or ordering of the solvent molecules (32,50).…”

Section: Enzymatic Digestionmentioning

confidence: 99%

Production of Hypoallergenic Antibacterial Peptides from Defatted Soybean Meal by a Membrane Associated Bioreactor: A Bioprocess Engineering Study with Comprehensive Product Characterization

Nath

Szécsi

Csehi

et al. 2017

Food Technol. Biotechnol.

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SummaryHypoallergenic antibacterial low-molecular-mass peptides were produced from defatted soybean meal in a membrane bioreactor. In the fi rst step, soybean meal proteins were digested with trypsin in the bioreactor, operated in batch mode. For the tryptic digestion of soybean meal protein, optimum initial soybean meal concentration of 75 g/L, temperature of 40 °C and pH=9.0 were determined. Aft er enzymatic digestion, low-molecular-mass peptides were purifi ed with cross-fl ow fl at sheet membrane (pore size 100 μm) and then with tubular ceramic ultrafi ltration membrane (molecular mass cut-off 5 kDa). Eff ects of transmembrane pressure and the use of a static turbulence promoter to reduce the concentration polarization near the ultrafi ltration membrane surface were examined and their positive eff ects were proven. For the fi ltration with ultrafi ltration membrane, transmembrane pressure of 3·10 5 Pa with 3-stage discontinuous diafi ltration was found optimal. The molecular mass distribution of purifi ed peptides using ultrafi ltration membrane was determined by a liquid chromatography-electrospray ionization quadrupole time-of-fl ight mass spectrometry setup. More than 96 % of the peptides (calculated as relative frequency) from the ultrafi ltration membrane permeate had the molecular mass M≤1.7 kDa and the highest molecular mass was found to be 3.1 kDa. The decrease of allergenic property due to the tryptic digestion and membrane fi ltration was determined by an enzyme-linked immunosorbent assay and it was found to exceed 99.9 %. It was also found that the peptides purifi ed in the ultrafi ltration membrane promoted the growth of Pediococcus acidilactici HA6111-2 and they possessed antibacterial activity against Bacillus cereus.

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Heat inactivation of lipase from psychrotrophic Pseudomonas fluorescens P38: Activation parameters and enzyme stability at low or ultra-high temperatures

Cited by 66 publications

References 22 publications

Lactam–amide graft copolymers as novel support for enzyme immobilization

Lactam–amide graft copolymers as novel support for enzyme immobilization

Characterization of xylose reductase extracted by CTAB-reversed micelles from Candida guilliermondii homogenate

Production of Hypoallergenic Antibacterial Peptides from Defatted Soybean Meal by a Membrane Associated Bioreactor: A Bioprocess Engineering Study with Comprehensive Product Characterization

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