Thermostable α-glucosidase produced by Bacillus caldovelox DSM411

1987 ◽  
Vol 33 (7) ◽  
pp. 614-618 ◽  
Author(s):  
Mary Giblin ◽  
Catherine T. Kelly ◽  
William M. Fogarty
Keyword(s):  
Thermal Stability ◽  
Molecular Weight ◽  
Isoelectric Point ◽  
Gel Filtration ◽  
Single Band ◽  
Original Activity ◽  
Protamine Sulphate ◽  
Barium Strontium ◽  
Sds Page ◽  
Thermal Stability Of

Bacillus caldovelox produces an intracellular α-glucosidase (EC 3.2.1.20). It is the most thermostable microbial α-glucosidase reported to date and a number of its properties are outlined here. It was purified by treatment with protamine sulphate and gel filtration on Sephadex G-150 and gave a single band on SDS–PAGE. The enzyme had highest activity on p-nitrophenyl-α-D-glucoside, which was 2.04 times higher than the activity on maltose, and it was inactive towards isomaltose. It had a molecular weight of 30 000 and an isoelectric point of pH 5.0. The enzyme operated most efficiently at pH 5.5–6.0 and at 50–60 °C. It possessed considerable pH stability, retaining 80% or more activity in the range pH 4.0–9.0. α-Glucosidases tend to be very unstable, but this enzyme was fully stable up to 60 °C for 1 h and retained 51% of its original activity on incubation at 70 °C over the same period. The presence of histidine, cysteine, and manganous ions improved the thermal stability of the enzyme considerably. EDTA, α,α′-dipyridyl, o-phenanthroline, barium, strontium, manganous ions, and glucose stimulated activity, while Tris, ribose, glucono-δ-lactone, and phenyl-α-D-glucoside inhibited activity.

scholarly journals Effect of heat treatment on re-solubility of potato proteins isolated from industrial potato fruit juice

2008 ◽  
Vol 54 (No. 4) ◽  
pp. 170-175 ◽  
Author(s):  
V. Bártová ◽  
J. Bárta
Keyword(s):  
Heat Treatment ◽  
Thermal Stability ◽  
Molecular Weight ◽  
Protease Inhibitors ◽  
Fruit Juice ◽  
Protein Isolate ◽  
Tuber Protein ◽  
Sds Page ◽  
Carboxypeptidase Inhibitor ◽  
Thermal Stability Of

The contribution deals with thermal stability and re-solubility of potato tuber proteins isolated by ethanol precipitation from industrial potato fruit juice. The protein isolate was exposed to the temperatures ranging from 25°C to 70°C. Patatin, the tuber protein with a high nutritious value, was detected by SDS-PAGE in the region of 39–43 kDa. Patatin was evaluated as thermal sensitive – temperatures above 30°C caused its strong insolubility. Potato protease inhibitors were detected in the region from 4.3 to 24 kDa. Thermal stability of potato protease inhibitors (region from 25 to 14 kDa) was higher, although the temperatures above 45°C caused denaturation and insolubility of most of the protease inhibitors. Extremely thermo-stable was potato carboxypeptidase inhibitor with molecular weight of 4.3 kDa that remained soluble even after having been exposed to the highest temperatures.

scholarly journals Physicochemical characteristics of chitosan from swimming crab (Portunus trituberculatus) shells prepared by subcritical water pretreatment

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Gengxin Hao ◽  
Yanyu Hu ◽  
Linfan Shi ◽  
Jun Chen ◽  
Aixiu Cui ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Molecular Weight ◽  
Sodium Hydroxide ◽  
Subcritical Water ◽  
Physicochemical Characteristics ◽  
Ash Content ◽  
Portunus Trituberculatus ◽  
Swimming Crab ◽  
Water Pretreatment ◽  
Thermal Stability Of

AbstractThe physicochemical properties of chitosan obtained from the shells of swimming crab (Portunus trituberculatus) and prepared via subcritical water pretreatment were examined. At the deacetylation temperature of 90 °C, the yield, ash content, and molecular weight of chitosan in the shells prepared via subcritical water pretreatment were 12.2%, 0.6%, and 1187.2 kDa, respectively. These values were lower than those of shells prepared via sodium hydroxide pretreatment. At the deacetylation temperature of 120 °C, a similar trend was observed in chitosan molecular weight, but differences in chitosan yield and ash content were not remarkable. At the same deacetylation temperature, the structures of chitosan prepared via sodium hydroxide and subcritical water pretreatments were not substantially different. However, the compactness and thermal stability of chitosan prepared via sodium hydroxide pretreatment was lower than those of chitosan prepared via subcritical water pretreatment. Compared with the chitosan prepared by sodium hydroxide pretreatment, the chitosan prepared by subcritical water pretreatment was easier to use in preparing oligosaccharides, including (GlcN)2, via enzymatic hydrolysis with chitosanase. Results suggested that subcritical water pretreatment can be potentially used for the pretreatment of crustacean shells. The residues obtained via this method can be utilized to prepare chitosan.

The effect of methyl and methoxy substituents on dianilines for a thermosetting polyimide system

2020 ◽  
Vol 32 (7) ◽  
pp. 801-822 ◽  
Author(s):  
John J La Scala ◽  
Greg Yandek ◽  
Jason Lamb ◽  
Craig M Paquette ◽  
William S Eck ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Molecular Weight ◽  
Glass Transition ◽  
Elevated Temperature ◽  
Methyl Substituent ◽  
Glass Transition Temperatures ◽  
High Performing ◽  
Methoxy Substituent ◽  
Acidic Conditions ◽  
Thermal Stability Of

4,4′-Methylenedianiline (MDA) is widely used in high-temperature polyimide resins, including polymerization of monomer reactants-15. The toxicity of MDA significantly limits the manufacturability using this resin. Modifying the substitution and electronics of MDA could allow for the reduction of toxicity while maintaining the high-performing properties of the materials derived from the modified MDA. The addition of a single methyl substituent, methoxy substituent, location of these substituents, and location of the amine relative to the phenolic bridge were modified as were other non-aniline diamines. Various anilines were condensed with paraformaldehyde under acidic conditions to yield dianilines. These dianilines and diamines were reacted with nadic anhydride and 3,3′,4,4′-benzophenonetetracarboxylic dianhydride in methanol to form the polyamic acid oligomers and heated at elevated temperature to form polyimide oligomers. It was found that the molecular weight of the oligomers derived from MDA alternatives was generally lower than that of MDA oligomers resulting in lower glass transition temperatures ( T gs) and degradation temperatures. Additionally, methoxy substituents further reduce the T g of the polymers versus methyl substituents and reduce the thermal stability of the resin. Methyl-substituted alternatives produced polyimides with similar T gs and degradation temperatures. The toxicity of the MDA alternatives was examined. Although a few were identified with reduced toxicities, the alternatives with properties similar to that of MDA also had high toxicities.

scholarly journals Isolation and Characterization of Two Proteins fromMoraxella catarrhalis That Bear a Common Epitope

1998 ◽  
Vol 66 (9) ◽  
pp. 4374-4381 ◽  
Author(s):  
John C. McMichael ◽  
Michael J. Fiske ◽  
Ross A. Fredenburg ◽  
Deb N. Chakravarti ◽  
Karl R. VanDerMeid ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Bacterial Attachment ◽  
Vaccine Candidates ◽  
Isolation And Characterization ◽  
Sds Page

ABSTRACT The UspA1 and UspA2 proteins of Moraxella catarrhalisare potential vaccine candidates for preventing disease caused by this organism. We have characterized both proteins and evaluated their vaccine potential using both in vitro and in vivo assays. Both proteins were purified from the O35E isolate by Triton X-100 extraction, followed by ion-exchange and hydroxyapatite chromatography. Analysis of the sequences of internal peptides, prepared by enzymatic and chemical cleavage of the proteins, revealed that UspA1 and UspA2 exhibited distinct structural differences but shared a common sequence including an epitope recognized by the monoclonal antibody 17C7. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), purified UspA1 exhibited a molecular weight of approximately 350,000 when unheated and a molecular weight of 100,000 after being heated for 10 min at 100°C. In contrast, purified UspA2 exhibited an apparent molecular weight of 240,000 by SDS-PAGE that did not change with the length of time of heating. Their sizes as determined by gel filtration were 1,150,000 and 830,000 for UspA1 and UspA2, respectively. Preliminary results indicate the proteins have separate functions in bacterial pathogenesis. Purified UspA1 was found to bind HEp-2 cells, and sera against UspA1, but not against UspA2, blocked binding of the O35E isolate to the HEp-2 cells. UspA1 also bound fibronectin and appears to have a role in bacterial attachment. Purified UspA2, however, did not bind fibronectin but had an affinity for vitronectin. Both proteins elicited bactericidal antibodies in mice to homologous and heterologous disease isolates. Finally, mice immunized with each of the proteins, followed by pulmonary challenge with either the homologous or a heterologous isolate, cleared the bacteria more rapidly than mock-immunized mice. These results suggest that UspA1 and UspA2 serve different virulence functions and that both are promising vaccine candidates.

Antibacterial Activities of Antibacterial Proteins/Peptides Isolated from Organs and Mucus of Clarias Gariepinus Reared at High Stocking Density

2012 ◽  
Vol 455-456 ◽  
pp. 455-460 ◽  
Author(s):  
Xiao Mei Wang ◽  
Wei Dai ◽  
Ke Zhing Xing ◽  
Tian Jun Li ◽  
Xin Wang
Keyword(s):  
Molecular Weight ◽  
Antibacterial Activity ◽  
Crude Protein ◽  
Clarias Gariepinus ◽  
Gel Filtration ◽  
Stocking Density ◽  
Antibacterial Activities ◽  
Edwardsiella Tarda ◽  
Bacterial Strains ◽  
Sds Page

. Antibacterial proteins/peptides are important parts of the innate immune system in Clarias gariepinus. To examine potential antibacterial proteins/peptides in organs and mucus of C. gariepinus, crude protein/peptide extracts were isolated with ammonium sulfate precipitation from mucus, skin, gill, suprabranchial organ and intestine. Following further extraction using Sephadex G-50 gel filtration chromatography, the proteins/peptides associated with two absorption peaks (AP1 and AP2) were pooled, respectively, and assayed for their antibacterial activities against Escherichia coli, Aeromonas hydrophila and Edwardsiella tarda. The results showed that AP1 and AP2 from all the sampled tissues and mucus at concentration of 100 mg mL-1 exhibited antibacterial activity against the tested bacterial strains. Differences in antibacterial activity were observed among sample extracts. The protein profiles of AP1 obtained by Tricine-SDS-PAGE gel showed a broad range of peptides/proteins, and molecular weight of the mutual abundant peptide obtained was about 27 kDa. Antibacterial activity of AP2 extracted from intestine was due to peptide with molecular weight of 5.5 kDa.

scholarly journals Biochemical isolation and physiological identification of the egg-laying hormone in Aplysia californica.

1976 ◽  
Vol 68 (2) ◽  
pp. 197-210 ◽  
Author(s):  
S Arch ◽  
P Earley ◽  
T Smock
Keyword(s):  
Molecular Weight ◽  
Isoelectric Point ◽  
Gel Electrophoresis ◽  
Biological Function ◽  
Aplysia Californica ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Egg Laying ◽  
Separation Procedure ◽  
Bag Cells

It has been determined that the bag cells of Aplysia californica produce two polypeptide species that comigrate on electrophoretic gels containing sodium dodecyl sulfate. By this separation procedure both species can be assigned a molecular weight of approximately 6,000. One of these molecules has an Rf of 0.65 on alkaline discontinuous electrophoresis gels, an isoelectric point at pH 4.8, a gel filtration molecular weight of approximately 12,000, and has no known biological function. The other does not enter alkaline disk gels, has an isoelectric point at approximately pH 9.3, shows a gel filtration molecular weight consistent with that determined by SDS gel electrophoresis, and is the egg-laying hormone.

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