scholarly journals Enzymic sulphation of p-nitrophenol and steroids by larval gut tissues of the southern armyworm (Prodenia eridania Cramer)

1972 ◽  
Vol 130 (2) ◽  
pp. 487-493 ◽  
Author(s):  
R. S. H. Yang ◽  
C. F. Wilkinson
Keyword(s):  
Enzyme Preparation ◽  
Soluble Fraction ◽  
Enzyme System ◽  
Endocrine Control ◽  
Southern Armyworm ◽  
Inorganic Sulphate

1. An enzyme system that catalyses the sulphation of p-nitrophenol, cholesterol, α-ecdysone, β-sitosterol, dehydroepiandrosterone, oestrone and four other steroids of plant and insect origin was obtained from the soluble fraction of southern-armyworm gut tissues. 2. The enzyme system required ATP and inorganic sulphate, and activity was slightly enhanced in the presence of GSH. 3. The properties of this enzyme system with respect to pH, temperature, substrate and protein concentrations and various cofactors and reagents were studied. At −23°C the enzyme preparation could be stored for 2 weeks without drastic loss of activity. At the end of storage for 1 month the loss of activity was approx. 21%. 4. The possible involvement of this enzyme system in insect endocrine control is discussed.

scholarly journals Studies on the enzymic degradation of L-serine O-sulphate by a rat liver preparation

1967 ◽  
Vol 105 (2) ◽  
pp. 467-472 ◽  
Author(s):  
J H Thomas ◽  
N. Tudball
Keyword(s):  
Rat Liver ◽  
Enzyme Preparation ◽  
Enzyme System ◽  
Metal Salts ◽  
Optimum Conditions ◽  
Enzyme Action ◽  
Inorganic Sulphate ◽  
Serine Dehydratase ◽  
Liver Preparation

1. The enzyme system of rat liver responsible for the degradation of l-serine O-sulphate was purified 300-fold and the optimum conditions for the activity were determined. 2. Inorganic sulphate, pyruvate and ammonia were found to be the products of enzyme action on lserine O-sulphate, being formed in equivalent amounts under all conditions examined. No free l-serine was detected as a product of enzyme action. 3. The enzyme preparation was free from other serine-metabolizing systems such as O-phospho-l-serine phosphatase and l-serine dehydratase. 4. The enzyme has a very narrow substrate specificity and is inactive towards a wide variety of related sulphate esters and amino acids. 5. Pyridoxal 5′-phosphate is capable of catalysing the non-enzymic breakdown of l-serine O-sulphate in the presence of metal salts to yield inorganic sulphate, pyruvate and ammonia as products. 6. The possible role of pyridoxal 5′-phosphate as a coenzyme in the enzymic degradation of l-serine O-sulphate is discussed.

scholarly journals Paenibacillus curdlanolyticus Strain B-6 Xylanolytic-Cellulolytic Enzyme System That Degrades Insoluble Polysaccharides

2006 ◽  
Vol 72 (4) ◽  
pp. 2483-2490 ◽  
Author(s):  
Patthra Pason ◽  
Khin Lay Kyu ◽  
Khanok Ratanakhanokchai
Keyword(s):  
Growth Phase ◽  
Enzyme Preparation ◽  
Enzyme System ◽  
Crude Enzyme ◽  
Cellulolytic Enzyme ◽  
Crude Enzyme Preparation ◽  
Multienzyme Complexes ◽  
Sds Page ◽  
Paenibacillus Curdlanolyticus ◽  
Cellulose Binding

ABSTRACT A facultatively anaerobic bacterium, Paenibacillus curdlanolyticus B-6, isolated from an anaerobic digester produces an extracellular xylanolytic-cellulolytic enzyme system containing xylanase, β-xylosidase, arabinofuranosidase, acetyl esterase, mannanase, carboxymethyl cellulase (CMCase), avicelase, cellobiohydrolase, β-glucosidase, amylase, and chitinase when grown on xylan under aerobic conditions. During growth on xylan, the bacterial cells were found to adhere to xylan from the early exponential growth phase to the late stationary growth phase. Scanning electron microscopic analysis revealed the adhesion of cells to xylan. The crude enzyme preparation was found to be capable of binding to insoluble xylan and Avicel. The xylanolytic-cellulolytic enzyme system efficiently hydrolyzed insoluble xylan, Avicel, and corn hulls to soluble sugars that were exclusively xylose and glucose. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of a crude enzyme preparation exhibited at least 17 proteins, and zymograms revealed multiple xylanases and cellulases containing 12 xylanases and 9 CMCases. The cellulose-binding proteins, which are mainly in a multienzyme complex, were isolated from the crude enzyme preparation by affinity purification on cellulose. This showed nine proteins by SDS-PAGE and eight xylanases and six CMCases on zymograms. Sephacryl S-300 gel filtration showed that the cellulose-binding proteins consisted of two multienzyme complexes with molecular masses of 1,450 and 400 kDa. The results indicated that the xylanolytic-cellulolytic enzyme system of this bacterium exists as multienzyme complexes.

STUDIES ON CORTICOSTERONE C-20 REDUCTION IN THE MOUSE

1962 ◽  
Vol 40 (1) ◽  
pp. 1797-1810 ◽  
Author(s):  
R. E. Krehbiel ◽  
A. F. Burton ◽  
Marvin Darrach
Keyword(s):  
Intravenous Injection ◽  
Mouse Liver ◽  
Enzyme Preparation ◽  
Soluble Fraction ◽  
Reductase Activity ◽  
Kinetics Of

The intravenous injection of corticosterone in the mouse was followed by liver assays for corticosterone and 20α- and 20β-dihydrocorticosterone. The 20α-epimer proved to be the more abundant product. Corticosterone 20α-reductase activity of mouse liver was shown to be associated with the dialyzed soluble fraction of the cell which served as an enzyme preparation for a study of certain properties of corticosterone 20α-reductase and the kinetics of the forward and reverse reactions.

scholarly journals Biosynthesis of vitamin B12: the preparative multi-enzyme synthesis of precorrin-3A and 20-methylsirohydrochlorin (a 2,7,20-trimethylisobacteriochlorin)

1996 ◽  
Vol 313 (1) ◽  
pp. 335-342 ◽  
Author(s):  
N. J. Patrick STAMFORD ◽  
Joël CROUZET ◽  
Béatrice CAMERON ◽  
Alex I. D. ALANINE ◽  
Andrew R. PITT ◽  
...  
Keyword(s):  
Vitamin B12 ◽  
Large Scale ◽  
Enzyme Preparation ◽  
Enzyme System ◽  
Enzyme Synthesis ◽  
High Yield ◽  
Pseudomonas Denitrificans ◽  
E Coli ◽  
Plasmid Construct ◽  
Porphobilinogen Synthase

The Bacillus subtilis genes hemB, hemC and hemD, encoding respectively the enzymes porphobilinogen synthase, hydroxymethylbilane synthase and uroporphyrinogen III synthase, have been expressed in Escherichia coli using a single plasmid construct. An enzyme preparation from this source converts 5-aminolaevulinic acid (ALA) preparatively and in high yield into uroporphyrinogen III. The Pseudomonas denitrificans genes cobA and cobI, encoding respectively the enzymes S-adenosyl-L-methionine:uroporphyrinogen III methyltransferase (SUMT) and S-adenosyl-L-methionine:precorrin-2 methyltransferase (SP2MT), were also expressed in E. coli. When SUMT was combined with the coupled-enzyme system that produces uroporphyrinogen III, precorrin-2 was synthesized from ALA, and when SP2MT was also added the product from the coupling of five enzymes was precorrin-3A. Both of these products are precursors of vitamin B12, and they can be used directly for biosynthetic experiments or isolated as their didehydro octamethyl esters in > 40% overall yield. The enzyme system which produces precorrin-3A is sufficiently stable to allow long incubations on a large scale, affording substantial quantities (15-20 mg) of product.

STEROIDOGENESIS IN EQUINE TESTIS

1970 ◽  
Vol 64 (1) ◽  
pp. 1-16 ◽  
Author(s):  
Ran Oh ◽  
Bun-ichi Tamaoki
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Isotope Dilution ◽  
Microsomal Fraction ◽  
Soluble Fraction ◽  
Enzyme System ◽  
Hydroxysteroid Dehydrogenase ◽  
Supernatant Fluid ◽  
Layer Chromatography

ABSTRACT When the cell-free homogenates (supernatant fluid at 800 × g) and the supernatant fluid at 10 000 × g of equine testis were incubated with 4-14C-labelled progesterone and 17α-hydroxyprogesterone, radioactive androstenedione and testosterone were isolated as the metabolites. Oestrone was also produced by the same equine testicular preparation from the above mentioned C-21 steroids, androstenedione and dehydroepiandrosterone, while 17β-oestradiol was obtained from the testosterone which had been incubated as the substrate. In addition to the androgens and the oestrogens which were obtained as the metabolites, 19-hydroxyandrostenedione, 20α-dihydroprogesterone and androst-5-ene-3β,17β-diol were identified as the metabolites by thin layer chromatography, chemical derivation procedures, and isotope dilution methods in the course of recrystallization. The testicular 19-hydroxylase and aromatizing enzyme system were found to be concentrated intracellularly in the microsomal fraction (10 000-105 000 × g precipitate), while the 20α-hydroxysteroid dehydrogenase which preferably converted progesterone into 20α-dihydroprogesterone were exclusively found in the soluble fraction or the supernatant fluid at 105 000 × g. The role and mechanism of aromatization by equine testicular preparations are discussed in relation to those of the placental microsomal aromatase.

OXIDATION OF SUGARS BY AN ENZYME PREPARATION FROMAEROBACTER AEROGENES

1955 ◽  
Vol 1 (9) ◽  
pp. 733-742 ◽  
Author(s):  
A. Dalby ◽  
A. C. Blackwood
Keyword(s):  
Metal Ions ◽  
Yeast Extract ◽  
Enzyme Preparation ◽  
Enzyme System ◽  
Divalent Metal ◽  
Ph Stability ◽  
Particulate Fraction ◽  
Divalent Metal Ions ◽  
Aerobacter Aerogenes ◽  
Crude Enzyme Preparation

Cell-free extracts of Aerobacter aerogenes grown on a medium containing yeast extract, glucose, and salts, oxidized D-α-fructoheptose (2-C-hydroxymethyl-D-glucose), glucose, gluconate, and other hexoses and pentoses. The enzymes were in a particulate fraction and were difficult to purify. This cell-free enzyme system required magnesium or certain other divalent metal ions as activators and was not stimulated by any coenzyme tested. Phosphorylation did not appear to be involved. The pH-stability and pH-activity curves for the crude enzyme preparation were plotted and the Kmvalue for D-α-fructoheptose determined. The same enzyme system is apparently involved for all substrates and appears to be specific for sugars having the same configuration as glucose at the second and fourth carbon atoms.

STUDIES ON CORTICOSTERONE C-20 REDUCTION IN THE MOUSE

1962 ◽  
Vol 40 (12) ◽  
pp. 1797-1810 ◽  
Author(s):  
R. E. Krehbiel ◽  
A. F. Burton ◽  
Marvin Darrach
Keyword(s):  
Intravenous Injection ◽  
Mouse Liver ◽  
Enzyme Preparation ◽  
Soluble Fraction ◽  
Reductase Activity ◽  
Kinetics Of

The intravenous injection of corticosterone in the mouse was followed by liver assays for corticosterone and 20α- and 20β-dihydrocorticosterone. The 20α-epimer proved to be the more abundant product. Corticosterone 20α-reductase activity of mouse liver was shown to be associated with the dialyzed soluble fraction of the cell which served as an enzyme preparation for a study of certain properties of corticosterone 20α-reductase and the kinetics of the forward and reverse reactions.

scholarly journals Bacterial attack on phenolic ethers: An enzyme system demethylating vanillic acid

1967 ◽  
Vol 102 (3) ◽  
pp. 826-841 ◽  
Author(s):  
N. J. Cartwright ◽  
A. R. W. Smith
Keyword(s):  
Formate Dehydrogenase ◽  
Soluble Fraction ◽  
Enzyme System ◽  
Reduced Glutathione ◽  
Ring Cleavage ◽  
Formaldehyde Dehydrogenase ◽  
Free System ◽  
Methyl Group ◽  
Oxidative Demethylation ◽  
A Cell

1. A cell-free system from Pseudomonas fluorescens catalysed the oxidative demethylation and subsequent ring-cleavage of vanillate, with uptake of 2.5 moles of oxygen/mole of substrate. 2. Demethylation involved absorption of 0.5 mole of oxygen/mole, and required reduced glutathione (GSH) and nucleotide (probably NADPH) as cofactors, with further possible requirements, the natures of which are discussed. 3. Incomplete evidence suggested that the aromatic ring was opened via protocatechuate and the appropriate oxygenase, with absorption of 1 mole of oxygen/mole of substrate, eventually yielding beta-oxoadipate. 4. The methyl group was removed sequentially as formaldehyde, formate and carbon dioxide, the steps catalysed respectively by formaldehyde dehydrogenase, which required GSH and NAD(+), and formate dehydrogenase. Each enzyme was cytochrome-linked and accounted for absorption of 0.5mole of oxygen/mole of substrate. 5. All enzymes except formate dehydrogenase, which was a cell-wall enzyme, resided in the soluble fraction of the extract. The demethylase could not be resolved because of unknown cofactor requirements.

scholarly journals Biosynthesis of galactan by a particulate enzyme preparation from Phaseolus aureus seedlings

1968 ◽  
Vol 106 (2) ◽  
pp. 355-360 ◽  
Author(s):  
James M. McNab ◽  
Clarence L. Villemez ◽  
Peter Albersheim
Keyword(s):  
Molecular Weight ◽  
Substrate Concentration ◽  
Enzyme Preparation ◽  
Enzyme System ◽  
Water Soluble ◽  
Partial Hydrolysis ◽  
Synthetase Activity ◽  
Phaseolus Aureus ◽  
Michaelis Constant ◽  
Soluble Polysaccharide

A particulate cell-free enzyme system was prepared from Phaseolus aureus shoots. This preparation was able to incorporate [14C]galactose from UDP-[14C]galactose into a water-soluble polysaccharide, which has a probable molecular weight of at least 4600. The only labelled component detectable in the polymer was shown to be [14C]galactose; two labelled oligosaccharides containing only [14C]galactose were isolated by partial hydrolysis. The galactan-synthesizing activity of this particulate preparation is maximal at 30° and pH7·1 in the presence of 5·0mm-magnesium chloride and 0·2m-sucrose. Although 3-day-old seedlings were used as a source of enzyme, it appears that 4- or 5-day-old beans contain greater synthetase activity. The enzyme system has an apparent Michaelis constant of 5·8×10−6m, and will catalyse the polymerization of galactose residues at the rate of 7·5mμmoles/mg. of protein/min. at a substrate concentration of 9·6mm.

THE INTERCONVERSION OF GLYCINE AND SERINE IN ZEA MAYS

1959 ◽  
Vol 37 (7) ◽  
pp. 887-894 ◽  
Author(s):  
A. H. W. Hauschild
Keyword(s):  
Zea Mays ◽  
Equilibrium Constant ◽  
Enzyme Preparation ◽  
Pyridoxal Phosphate ◽  
Soluble Fraction ◽  
Activity Curve

Glycine and formaldehyde are converted into serine in the presence of a dialyzed, lyophilized enzyme preparation from corn seedlings, with tetrahydropteroylglutamic acid and pyridoxal phosphate as coenzymes. The equilibrium constant of the reaction was calculated for the system at 37.5 °C as K = 3.1 × 103. The pH activity curve showed a maximum between 6.6 and 7.0. The effects of the concentrations of the coenzymes were studied. The glycine–serine interconverting enzyme is present throughout the seedling and occurs exclusively in the soluble fraction of the cells.

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