scholarly journals Purification and characterization of hemocyte phenoloxidases in Chilo suppressalis walker (Lepidoptera: Crambidae)

2015 ◽  
Vol 67 (4) ◽  
pp. 1119-1125 ◽  
Author(s):  
Seyyedeh Mirhaghparast ◽  
Arash Zibaee ◽  
Hassan Hoda ◽  
Mahmoud Fazeli-Dinan

In the current study, two phenoloxidases (POs) from the larvae of Chilo suppressalis Walker were extracted and purified by column chromatography using Sepharyl G-100 and DEAE-Cellulose fast flow column. Two proteins possessing PO activity, named as POI and POII, were extracted by purification, 5.08- and 5.62-fold, respectively, with 8.94% and 7.31% recoveries, respectively. Also, the specific activities of POI and POII were 0.478 and 0.529 U/mg protein, respectively. Finally, the molecular weights of POI and POII were calculated as 94.6 and 95.7 kDa, respectively. Kinetic parameters of the purified phenoloxidases by Lineweaver-Burk analysis were Vmax of 2.27 and 1.11 U/mg protein and Km of 15.51 and 17.31 mM for POI and POII, respectively. Mg2+ and Cu2+ significantly increased the PO activities. Ca2+ decreased the activity of POI and showed no statistical effects on POII activity. EDTA and DTC significantly inhibited the activities of the purified enzymes, while triethylenetetramine hexaacetic acid (TTHA) and RGTA showed no significant effects on enzymatic activities.

2015 ◽  
Vol 55 (2) ◽  
pp. 179-186 ◽  
Author(s):  
Hossein Firouzbakht ◽  
Arash Zibaee ◽  
Hassan Hoda ◽  
Mohammad Mehdi Sohani

Abstract The entomopathogenic fungi-like Beauveria bassiana must penetrate via the integument of an insect to reach the hemocoel. Since proteins are the molecules responsible for integument strength in insects, the proteins must synthesise the cuticle degrading proteases which will then enable the proteases to penetrate. It is important to determine the biochemical properties of these proteases so that fungal virulence can be better understood. In the current study, a recently collected isolate of B. bassiana, namely AM-118, was inoculated in liquid media containing 0.5% of Andrallus spinidens Fabricus cuticle to obtain specific proteases. The crude samples were purified via a three step process using ammonium sulfate, Sepharyl G-100, and DEAE-Cellulose Fast Flow. The results revealed two proteases known as subtilisin-like (Pr1), and trypsin-like (Pr2), with the molecular weights of 105 and 103 kDa. The optimal pH and temperature values were found to be 8 and 35°C for Pr1 and 8 and 40°C for Pr2, respectively. Inhibitors like AEBSF, EDTA, TPCK, and phenanthroline significantly affected proteolytic activities. Here, we reported two fungal proteases by high molecular weight from an Iranian isolate of B. bassiana. These findings will help us to better understand fungal virulence against insects.


1993 ◽  
Vol 71 (7-8) ◽  
pp. 406-410
Author(s):  
Les Jones ◽  
Sharon Churchill ◽  
Perry Churchill

D-β-Hydroxybutyrate dehydrogenase (BDH), a lipid-requiring enzyme, has been cloned into pUC18, expressed in Escherichia coli, and purified to homogeneity. The apoenzyme, i.e., the enzyme devoid of phospholipid, has no activity, but can be activated by phospholipid to a specific activity of 129 μmol/(min∙mg). The functional properties of the enzyme expressed in E. coli were compared with the enzyme purified from rat liver. The specific activities, kinetic parameters, and phospholipid activation profiles were virtually identical. These results indicate that the expression of the enzyme in E. coli is a viable method for producing active functional BDH and should allow for the production of specifically altered BDH molecules.Key words: D-β-hydroxybutyrate dehydrogenase, cloning, expression, lipid requiring.


1982 ◽  
Vol 207 (3) ◽  
pp. 459-470 ◽  
Author(s):  
J D Hayes ◽  
G H D Clarkson

Rat liver glutathione S-transferases have previously been defined by their elution behaviour from DEAE-cellulose and CM-cellulose as M, E, D, C, B, A and AA. These enzymes are dimeric proteins which comprise subunits of mol.wt. 22 000 (Ya), 23 500 (Yb) or 25 000 (Yc). Evidence is presented that YaYa protein, one of two previously described lithocholate-binding proteins which exhibit transferase activity, is an additional enzyme which is not included in the M, E, D, C, B, A and AA nomenclature. We therefore propose that this enzyme is designated transferase YaYa. Transferases YaYa, C, A and AA have molecular weights of 44 000, 47 000, 47 000 and 50 000 respectively and each comprises two subunits of identical size. These enzymes were purified to allow a study of their structural and functional relationships. In addition, transferase A was further resolved into three forms (A1, A2 and A3) which possess identical activities and structures and appear to be the product of a single gene. Transferases YaYa, C, A and AA each had distinct enzymic properties and were inhibited by cholate. The recently proposed proteolytic model, which attributes the presence of multiple forms of glutathione S-transferase activity to partial proteolysis of transferase AA, was tested and shown to be highly improbable. Peptide maps showed significant differences between transferases YaYa, C, A and AA. Immunotitration studies demonstrated that antisera raised against transferases YaYa and C did not precipitate transferase AA.


Author(s):  
Rahma R. Z. Mahdy ◽  
Shaimaa A. Mo’men ◽  
Marah M. Abd El-Bar ◽  
Emad M. S. Barakat

Abstract Background Insect lipid mobilization and transport are currently under research, especially lipases and lipophorin because of their roles in the production of energy and lipid transport at a flying activity. The present study has been conducted to purify intracellular fat body lipase for the first time, from the last larval instar of Galleria mellonella. Results Purification methods by combination of ammonium sulfate [(NH4)2SO4] precipitation and gel filtration using Sephadex G-100 demonstrated that the amount of protein and the specific activity of fat body lipase were 0.008633 ± 0.000551 mg/ml and 1.5754 ± 0.1042 μmol/min/mg protein, respectively, with a 98.9 fold purity and recovery of 50.81%. Hence, the sephadex G-100 step was more effective in the purification process. SDS-PAGE and zymogram revealed that fat body lipase showed two monomers with molecular weights of 178.8 and 62.6 kDa. Furthermore, biochemical characterization of fat body lipase was carried out through testing its activities against several factors, such as different temperatures, pH ranges, metal ions, and inhibitors ending by determination of their kinetic parameters with the use of p-nitrophenyl butyrate (PNPB) as a substrate. The highest activities of enzyme were determined at the temperature ranges of 35–37 °C and 37–40 °C and pH ranges of 7–9 and 7–10. The partially purified enzyme showed significant stimulation by Ca2+, K+, and Na+ metal ions indicating that fat body lipase is metalloproteinase. Lipase activity was strongly inhibited by some inhibitors; phenylmethylsulfonyl fluoride (PMSF), ethylene-diaminetetractic acid (EDTA), and ethylene glycoltetraacetic acid (EGTA) providing evidence of the presence of serine residue and activation of enzymes by metal ions. Kinetic parameters were 0.316 Umg− 1 Vmax and 301.95 mM Km. Conclusion Considering the purification of fat body lipase from larvae and the usage of some inhibitors especially ion chelating agents, it is suggested to develop a successful control of Galleria mellonella in near future by using lipase inhibitors.


1975 ◽  
Vol 21 (12) ◽  
pp. 2019-2027
Author(s):  
M. Laguerre ◽  
R. Turcotte

The tuberculin activity of protoplasmic extracts isolated from living BCG was purified successively by gel filtration on Sephadex G-100 and G-75, and by electrophoresis on 7.5% and on gradient (6–18%) polyacrylamide gels. The tuberculin-active fractions, as determined in BCG-sensitized guinea pigs, were used as the starting material for each of the following fractionation steps.The physicochemical properties and the antigenic activity of the biologically active fractions have shown that a single component, or only a few ones with similar properties, possessed high tuberculin activity. These active components were proteins having relatively high molecular weights (about 72 000) and could behave as antigens.


1971 ◽  
Vol 124 (2) ◽  
pp. 337-343 ◽  
Author(s):  
Abraham Spector ◽  
Lu-Ku Li ◽  
Robert C. Augusteyn ◽  
Arthur Schneider ◽  
Thomas Freund

α-Crystallin was isolated from calf lens periphery by chromatography on DEAE-cellulose and gel filtration. Three distinct populations of macromolecules have been isolated with molecular weights in the ranges approx. 6×105−9×105, 0.9×106−4×106and greater than 10×106. The concentration of macromolecules at the molecular-weight limits of a population are very low. The members of the different populations do not appear to be in equilibrium with each other. Further, in those molecular-weight fractions investigated, no equilibrium between members of the same population was observed. The population of lowest molecular weight comprises 65–75% of the total material. The amino acid and subunit composition of the different-sized fractions appear very similar, if not identical. The only chemical difference observed between the fractions is the presence of significant amounts of sugar in the higher-molecular-weight fractions. Subunit molecular weights of approx. 19.5×103and 22.5×103were observed for all α-crystallin fractions.


1970 ◽  
Vol 1 (2) ◽  
pp. 164-168
Author(s):  
Thomas M. Daniel ◽  
Lavenia E. Ferguson

Two proteins have been purified from culture filtrates of Mycobacterium tuberculosis , H 37 Ra strain by a procedure combining gel filtration, diethylaminoethyl (DEAE)-cellulose chromatography, and zone electrophoresis. The two proteins are similar in molecular weight but differ slightly in charge. The faster migrating protein, designated a 1 , is not antigenic. The slower migrating protein, designated a 2 , is antigenic both with respect to antisera and as a skin-testing antigen.


1990 ◽  
Vol 269 (1) ◽  
pp. 13-18 ◽  
Author(s):  
Y Homma ◽  
Y Emori ◽  
F Shibasaki ◽  
K Suzuki ◽  
T Takenawa

A novel bovine spleen phosphoinositide-specific phospholipase C (PLC) has been identified with respect to immunoreactivity with four independent antibodies against each of the PLC isoenzymes, and purified to near homogeneity by sequential column chromatography. Spleen contains three of the isoenzymes: two different gamma-types [gamma 1 and gamma 2, originally named as PLC-gamma [Rhee, Suh, Ryu & Lee (1989) Science 244, 546-550] and PLC-IV [Emori, Homma, Sorimachi, Kawasaki, Nakanishi, Suzuki & Takenawa (1989) J. Biol. Chem. 264, 21885-21890] respectively] and delta-type of the enzyme, but PLC-gamma 1 is separated from the PLC-gamma 2 pool by the first DEAE-cellulose column chromatography. Subsequently, PLC-delta is dissociated on the third heparin-Sepharose column chromatography. The purified enzyme has a molecular mass of 145 kDa on SDS/polyacrylamide-gel electrophoresis and a specific activity of 12.8 mumol/min per mg with phosphatidylinositol 4,5-bisphosphate as substrate. This enzyme activity is dependent on Ca2+ for hydrolysis of all these phosphoinositides. None of the other phospholipids examined could be its substrate at any concentration of Ca2+. The optimal pH of the enzyme is slightly acidic (pH 5.0-6.5).


1979 ◽  
Vol 178 (2) ◽  
pp. 279-287 ◽  
Author(s):  
D K Podolsky ◽  
M M Weiser

A low-molecular-weight acceptor of galactosyltransferase activity was detected in sera and effusions of patients with extensive maligant disease. This substance was purified to homogeneity from both human serum and effusion by using sequential charcoal/Celite and DEAE-cellulose column chromatography. The purified acceptor was shown to act as substrate for both purified normal and cancer-associated human galactosyltransferase (EC 2.4.1.22) isoenzymes, but had a higher affinity for the cancer-associated isoenzyme (Km = 20 microM) than for the normal isoenzyme (Km = 500 microM). The substrate was found to be a glycopeptide with mol.wt. approx. 3600 determined by polyacrylamide-gel chromatography. Carbohyydate analysis demonstrated only the presence of glucosamine and mannose. Amino acid analysis revealed that the peptide moiety consisted of eight different amino acids, including two residues of asparagine and one residue of serine, but no threonine. These structural data suggest that the acceptor is a fraction of an asparagine-glucosamine type of glycoprotein.


1986 ◽  
Vol 64 (7) ◽  
pp. 638-646 ◽  
Author(s):  
Peter C. Loewen ◽  
Jacek Switala

Catalase (hydroperoxidase II or HPII) of Escherichia coli K12 has been purified using a protocol that also allows the purification of the second catalase HPI in large amounts. The purified HPII was found to have equal amounts of two subunits with molecular weights of 90 000 and 92 000. Only a single 92 000 subunit was present in the immunoprecipitate created when HPII antiserum was added directly to a crude extract, suggesting that proteolysis was responsible for the smaller subunit. The apparent native molecular weight was determined to be 532 000, suggesting a hexamer structure for the enzyme, an unusual structure for a catalase. HPII was very stable, remaining maximally active over the pH range 4–11 and retaining activity even in a solution of 0.1% sodium dodecyl sulfate and 7 M urea. The heme cofactor associated with HPII was also unusual for a catalase, in resembling heme d (a2) both spectrally and in terms of solubility. On the basis of heme-associated iron, six heme groups were associated with each molecule of enzyme or one per subunit.


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