Characterization of an enzyme from Rhizoctonia praticola which polymerizes phenolic compounds

1979 ◽  
Vol 25 (2) ◽  
pp. 229-233 ◽  
Author(s):  
Jean-Marc Bollag ◽  
Roy D. Sjoblad ◽  
Shu-Yen Liu

An extracellular phenol oxidase from the fungus Rhizoctonia praticola which polymerizes various xenobiotic phenols was isolated and characterized. The enzyme was purified by DEAE-cellulose and Sephadex G-200 chromatography followed by preparative polyacrylamide gel electrophoresis. Atomic absorption and EPR spectroscopy indicated the presence of copper, and SDS gel electrophoresis revealed a molecular weight of 78 000. With 2,6-dimethoxyphenol as substrate, the enzyme showed a pH optimum of 6.7–6.9, and a temperature optimum of 40 °C. According to these and additional characteristics it appears that the enzyme belongs to the class of laccases.

1981 ◽  
Vol 195 (3) ◽  
pp. 545-560 ◽  
Author(s):  
Heinz Fankhauser ◽  
Jerome A. Schiff ◽  
Leonard J. Garber

Extracts of Chlorella pyrenoidosa, Euglena gracilis var. bacillaris, spinach, barley, Dictyostelium discoideum and Escherichia coli form an unknown compound enzymically from adenosine 5′-phosphosulphate in the presence of ammonia. This unknown compound shares the following properties with adenosine 5′-phosphoramidate: molar proportions of constituent parts (1 adenine:1 ribose:1 phosphate:1 ammonia released at low pH), co-electrophoresis in all buffers tested including borate, formation of AMP at low pH through release of ammonia, mass and i.r. spectra and conversion into 5′-AMP by phosphodiesterase. This unknown compound therefore appears to be identical with adenosine 5′-phosphoramidate. The enzyme that catalyses the formation of adenosine 5′-phosphoramidate from ammonia and adenosine 5′-phosphosulphate was purified 1800-fold (to homogeneity) from Chlorella by using (NH4)2SO4 precipitation and DEAE-cellulose, Sephadex and Reactive Blue 2–agarose chromatography. The purified enzyme shows one band of protein, coincident with activity, at a position corresponding to 60000–65000 molecular weight, on polyacrylamide-gel electrophoresis, and yields three subunits on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis of 26000, 21000 and 17000 molecular weight, consistent with a molecular weight of 64000 for the native enzyme. Isoelectrofocusing yields one band of pI4.2. The pH optimum of the enzyme-catalysed reaction is 8.8. ATP, ADP or adenosine 3′-phosphate 5′-phosphosulphate will not replace adenosine 5′-phosphosulphate, and the apparent Km for the last-mentioned compound is 0.82mm. The apparent Km for ammonia (assuming NH3 to be the active species) is about 10mm. A large variety of primary, secondary and tertiary amines or amides will not replace ammonia. One mol.prop. of adenosine 5′-phosphosulphate reacts with 1 mol.prop. of ammonia to yield 1 mol.prop. each of adenosine 5′-phosphoramidate and sulphate; no AMP is found. The highly purified enzyme does not catalyse any of the known reactions of adenosine 5′-phosphosulphate, including those catalysed by ATP sulphurylase, adenosine 5′-phosphosulphate kinase, adenosine 5′-phosphosulphate sulphotransferase or ADP sulphurylase. Adenosine 5′-phosphoramidate is found in old samples of the ammonium salt of adenosine 5′-phosphosulphate and can be formed non-enzymically if adenosine 5′-phosphosulphate and ammonia are boiled. In the non-enzymic reaction both adenosine 5′-phosphoramidate and AMP are formed. Thus the enzyme forms adenosine 5′-phosphoramidate by selectively speeding up an already favoured reaction.


2013 ◽  
Vol 641-642 ◽  
pp. 906-909
Author(s):  
Chun Zhi Zhang ◽  
Ming Chen ◽  
Hai Chen Guo ◽  
Guo Ren Zu ◽  
Li Chen

The ginsenoside-hydrolyzing β-glucosidase that can converse the major ginsenosides into the minor ginsenosides was isolated from wheat bran, and the enzyme was purified and characterized. The crude enzyme solution extracted from wheat bran could hydrolyse the protopanaxadiol-type ginsenosides such as Rb1, Rc, Rd and Rg3, but could not hydrolyse the protopanaxatriol-type ginsenosides such as Re and Rg2. The enzyme fractionated on the DEAE-Cellulose DE-52 column was purified to one spot in SDS polyacrylamide gel electrophoresis, and the molecular weight of enzyme in the fraction 34, 47, and 61 was approximately 62 kDa, 62 kDa, and 68 kDa, respectively.


1974 ◽  
Vol 31 (01) ◽  
pp. 072-085 ◽  
Author(s):  
M Kopitar ◽  
M Stegnar ◽  
B Accetto ◽  
D Lebez

SummaryPlasminogen activator was isolated from disrupted pig leucocytes by the aid of DEAE chromatography, gel filtration on Sephadex G-100 and final purification on CM cellulose, or by preparative gel electrophoresis.Isolated plasminogen activator corresponds No. 3 band of the starting sample of leucocyte cells (that is composed from 10 gel electrophoretic bands).pH optimum was found to be in pH range 8.0–8.5 and the highest pH stability is between pH range 5.0–8.0.Inhibition studies of isolated plasminogen activator were performed with EACA, AMCHA, PAMBA and Trasylol, using Anson and Astrup method. By Astrup method 100% inhibition was found with EACA and Trasylol and 30% with AMCHA. PAMBA gave 60% inhibition already at concentration 10–3 M/ml. Molecular weight of plasminogen activator was determined by gel filtration on Sephadex G-100. The value obtained from 4 different samples was found to be 28000–30500.


1979 ◽  
Author(s):  
M Ribieto ◽  
J Elion ◽  
D Labie ◽  
F Josso

For the purification of the abnormal prothrombin (Pt Metz), advantage has been taken of the existence in the family of three siblings who, being double heterozygotes for Pt Metz and a hypoprothrombinemia, have no normal Pt. Purification procedures included barium citrate adsorption and chromatography on DEAE Sephadex as for normal Pt. As opposed to some other variants (Pt Barcelona and Madrid), Pt Metz elutes as a single symetrical peak. By SDS polyacrylamide gel electrophoresis, this material is homogeneous and appears to have the same molecular weight as normal Pt. Comigration of normal and abnormal Pt in the absence of SDS, shows a double band suggesting an abnormal charge for the variant. Pt Metz exhibits an identity reaction with the control by double immunodiffusion. Upon activation by factor Xa, Pt Metz can generate amydolytic activity on Bz-Phe-Val-Arg-pNa (S2160), but only a very low clotting activity. Clear abnormalities are observed in the cleavage pattern of Pt Metz when monitored by SDS gel electrophoresis. The main feature are the accumulation of prethrombin l (Pl) and the appearance of abnormal intermediates migrating faster than Pl.


1985 ◽  
Vol 63 (10) ◽  
pp. 2262-2266 ◽  
Author(s):  
A. V. Arjunwadkar ◽  
S. Raghupathi Rami Reddy

Arginine kinase in claw muscle extracts of the scorpion, Palamneus phipsoni, was characterized. The enzyme, with a pH optimum of 8.5 in the direction of phosphoarginine synthesis, showed activation by Mg2+, high specificity towards L-arginine as the guanidino substrate, slight inhibition by high concentrations of L-arginine and ATP, and a molecular weight of 33 500. On polyacrylamide gel electrophoresis at pH 8.3 the enzyme migrated to the anode as a single molecular species. In addition to the claw muscle, the enzyme activity was also found to be present in the heart, alimentary canal, hepatopancreas, and nervous system. In general, scorpion muscle arginine kinase appears to be similar in its properties to the enzyme from other arthropods.


1998 ◽  
Vol 64 (8) ◽  
pp. 3029-3035 ◽  
Author(s):  
David J. Bowen ◽  
Jerald C. Ensign

ABSTRACT Photorhabdus luminescens is a gram-negative enteric bacterium that is found in association with entomopathogenic nematodes of the family Heterorhabditidae. The nematodes infect a variety of soil-dwelling insects. Upon entering an insect host, the nematode releases P. luminescens cells from its intestinal tract, and the bacteria quickly establish a lethal septicemia. When grown in peptone broth, in the absence of the nematodes, the bacteria produce a protein toxin complex that is lethal when fed to, or injected into the hemolymph of, Manduca sexta larvae and several other insect species. The toxin purified as a protein complex which has an estimated molecular weight of 1,000,000 and contains no protease, phospholipase, or hemolytic activity and only a trace of lipase activity. The purified toxin possesses insecticidal activity whether injected or given orally. Analyses of the denatured complex by sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed it to be composed of several protein subunits ranging in size from 30 to 200 kDa. The complex was further separated by native gel electrophoresis into three components, two of which retained insecticidal activity. The purified native toxin complex was found to be active in nanogram concentrations against insects representing four orders of the classInsecta.


1987 ◽  
Vol 244 (1) ◽  
pp. 219-224 ◽  
Author(s):  
J M Jacobs ◽  
N J Jacobs

The protoporphyrinogen-oxidizing enzyme from Triton X-100 extracts of the mitochondrial and etioplast fractions of etiolated barley was purified by using ion-exchange and hydroxyapatite chromatography. The purified enzyme from both organelle fractions exhibited a Km of 5 microM and was labile to mild heat and acidification. The pH optimum (5-6) and the substrate-specificity (mesoporphyrinogen was oxidized as rapidly as protoporphyrinogen) revealed properties very different from the protoporphyrinogen-oxidizing enzyme of rat liver or yeast mitochondria, which is specific for protoporphyrinogen as substrate. The purest fractions showed a polypeptide band corresponding to an Mr of approx. 36,000 on SDS/polyacrylamide-gel electrophoresis. This is the first purification and characterization of the enzyme from a plant, and indicates no readily detectable differences between the enzyme isolated from mitochondrial or etioplast fractions, although only the latter organelle has the capacity for both haem and chlorophyll synthesis.


1978 ◽  
Vol 169 (2) ◽  
pp. 287-295 ◽  
Author(s):  
B Jasani ◽  
M K Jasani ◽  
M D Talbot

Two types of acid proteinase activity found in rabbit skin homografts were characterized by studying the effect of temperature, pH and polyacrylamide-gel electrophoresis. Their chromatographic behaviour was characterized on DEAE-cellulose, Sephadex G-75, G-100 and G-200, and their molecular weights were estimated by gel filtration. One of the acid proteinases in the homograft resembled cathepsin D (EC 3.4.23.5) of normal skin. The other acid proteinase differed from cathepsin D with respect to heat inactivation, pH optimum and molecular weight; it was not inactivated on heating at 60 degrees C for 60 min, its pH optimum was 2.5 and its molecular weight measured by Sephadex G-100 chromatography was 100 000. In all these respects, the heat-stable proteinase resembles cathepsin E (EC 3.4.23.5) of rabbit polymorphonuclear leucocytes.


1973 ◽  
Vol 51 (5) ◽  
pp. 709-720 ◽  
Author(s):  
John J. Monahan ◽  
Ross H. Hall

A general method for isolation and fractionation of chromatin into its four major components, DNA, RNA, histories, and nonhistone proteins, is described. The procedure avoids the use of strongly acidic or alkaline conditions, or the use of ionic detergents or phenol. As few as 14 × 106 cells can be used. The procedure is reasonably rapid and has been used successfully with a number of tissue culture cell lines. The chromatin components are dissociated in a 3 M NaCl – 5 M urea solution containing 2-mercaptoethanol and EDTA. The DNA and high molecular weight RNA are collected by high-speed centrifugation and DNA is separated from the RNA by means of Cs2SO4 equilibrium density centrifugation. The histones, nonhistone proteins, and low molecular weight RNA's are fractionated using DEAE-cellulose column chromatography and polyacrylamide gel electrophoresis. A small amount (< 1%) of protein is present in the DNA and RNA fractions. At least 11 low molecular weight RNA subfractions can be detected by means of polyacrylamide gel electrophoresis.


1988 ◽  
Vol 6 (2) ◽  
pp. 53-59 ◽  
Author(s):  
E.E. Sanchez ◽  
R.A. Menendez ◽  
L.S. Daley ◽  
R.B. Boone ◽  
O.L. Jahn ◽  
...  

An investigation of available Cydonia (Cydonia oblonga Mill., quince, membrillo) germplasm by isozyme staining of anionic polyacrylamide gradient electrophoresis gels is described. The isozymes of acid phosphatase, esterase, peroxidase and phenol oxidase showed most diversity and usefulness for this purpose. Eleven groups of quince and two groups of x Pyronia (quince-pear crosses) were distinguished by their isozyme patterns. These patterns distinguish between groups of clonal accessions, and the patterns were constant for each accession during the test period (December, 1986 to August, 1987). Thus, these patterns were considered to represent genetic characteristics suitable for identification purposes. The diversity of isozyme patterns was much less than in Corylus and Pyrus populations previously sampled; and less than that of a restricted pool of apple cultivars previously examined.


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