Kinetics and thermodynamics of thermal inactivation of partially purified bacteriocin from Pseudomonas aeroginosa

2020 ◽  
Author(s):  
P. Muthukumaran ◽  
R. Janani ◽  
S. Sivamani ◽  
N. Sivarajasekar ◽  
T. Pradeepika ◽  
...  
Keyword(s):  
Thermal Inactivation ◽  
Kinetics And Thermodynamics

scholarly journals Kinetics and Thermodynamics of Thermal Inactivation of β-Galactosidase from Aspergillus oryzae

2018 ◽  
Vol 61 (0) ◽  
Author(s):  
Manuela Poletto Klein ◽  
Voltaire Sant’Ana ◽  
Plinho Francisco Hertz ◽  
Rafael Costa Rodrigues ◽  
Jorge Luiz Ninow
Keyword(s):  
Aspergillus Oryzae ◽  
Thermal Inactivation ◽  
Kinetics And Thermodynamics

scholarly journals Kinetics and thermodynamics of thermal inactivation for recombinant Escherichia coli cellulases, cel12B, cel8C, and polygalacturonase, peh28; biocatalysts for biofuel precursor production

2020 ◽  
Author(s):  
Eman Ibrahim ◽  
Ahmed Mahmoud ◽  
Kim D Jones ◽  
Keith E Taylor ◽  
Ebtesam N Hosseney ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Thermal Stability ◽  
Lignocellulosic Biomass ◽  
Thermal Inactivation ◽  
Biomass Conversion ◽  
Industrial Applications ◽  
Recombinant Escherichia Coli ◽  
Thermal Stabilities ◽  
Kinetics And Thermodynamics ◽  
Lignocellulosic Biomass Conversion

Abstract Lignocellulosic biomass conversion using cellulases/polygalacturonases is a process that can be progressively influenced by several determinants involved in cellulose microfibril degradation. This article focuses on the kinetics and thermodynamics of thermal inactivation of recombinant Escherichia coli cellulases, cel12B, cel8C and a polygalacturonase, peh 28, derived from Pectobacterium carotovorum sub sp. carotovorum. Several consensus motifs conferring the enzymes’ thermal stability in both cel12B and peh28 model structures have been detailed earlier, which were confirmed for the three enzymes through the current study of their thermal inactivation profiles over the 20–80°C range using the respective activities on carboxymethylcellulose and polygalacturonic acid. Kinetic constants and half-lives of thermal inactivation, inactivation energy, plus inactivation entropies, enthalpies and Gibbs free energies, revealed high stability, less conformational change and protein unfolding for cel12B and peh28 due to thermal denaturation compared to cel8C. The apparent thermal stability of peh28 and cel12B, along with their hydrolytic efficiency on a lignocellulosic biomass conversion as reported previously, makes these enzymes candidates for various industrial applications. Analysis of the Gibbs free energy values suggests that the thermal stabilities of cel12B and peh28 are entropy-controlled over the tested temperature range.

Kinetics and thermodynamics of thermal inactivation of the antimicrobial peptide cerein 8A

2009 ◽  
Vol 91 (2) ◽  
pp. 223-227 ◽  
Author(s):  
Rosiele Lappe ◽  
Florencia Cladera-Olivera ◽  
Ana Paula Melo Dominguez ◽  
Adriano Brandelli
Keyword(s):  
Antimicrobial Peptide ◽  
Thermal Inactivation ◽  
Kinetics And Thermodynamics

Mechanism of Inhibitory Action on Platelet Activation of a Phospholipase A2 Isolated from Lachesis muta (Bushmaster) Snake Venom

1997 ◽  
Vol 78 (05) ◽  
pp. 1372-1380 ◽  
Author(s):  
André L Fuly ◽  
Olga L T Machado ◽  
Elias W Alves ◽  
Célia R Carlinis
Keyword(s):  
Platelet Aggregation ◽  
Enzymatic Activity ◽  
Phospholipase A2 ◽  
Inhibitory Activity ◽  
Thermal Inactivation ◽  
Anticoagulant Activity ◽  
Gel Filtration ◽  
Apparent Molecular Weight ◽  
Crude Venom ◽  
Lachesis Muta

SummaryCrude venom from Lachesis muta exhibited procoagulant, proteolytic and phospholipase A2 activities. A phospholipase A2, denoted LM-PLA2 was purified from L. muta venom to homogeneity, through a combination of chromatographic steps involving gel-filtration on Sephacryl S-200 HR and reverse phase chromatography on a C2/C18 column. LM-PLA2 presented a single polypeptide chain with an isoelectric point at pH 4.7 and apparent molecular weight of 17 kDa. Partial aminoacid sequence indicated a high degree of homology for LM-PLA2 with other PLA2 from different sources.LM-PLA2 displayed a potent enzymatic activity as measured by indirect hemolysis of red blood cells but it was neither lethal when injected i.p. into mice nor did it present anticoagulant activity. Furthermore, LM-PLA2 displayed a moderate inhibitory activity on the aggregation of rabbit platelets induced by low levels of ADP, thrombin and arachidonate. In contrast, platelet aggregation induced by high doses of collagen was strongly inhibited by LM-PLA2 as well as ATP-release. Treatment of the protein with p-bromophenacyl bromide or 2-mercapto-ethanol, as well as thermal inactivation studies, suggested that the platelet inhibitory effect of LM-PLA2 is dependent on its enzymatic activity. Thus, the platelet inhibitory activity of LM-PLA2 was shown to be dependent on the hydrolysis of plasma phospholipids and/or lipoproteins, most probably those rich in phosphatidylcholine. Surprisingly, lyso-phosphatidylcholine released by LM-PLA2 from plasma was shown to preferentially inhibited collagen-induced platelet aggregation, in contrast to other PLA2s, whose plasma hydrolytic products indistinctly affect platelet’s response to several agonists.

Sign in / Sign up

Export Citation Format

Share Document