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1.
Neutral and acidic polysaccharides and their protein complexes were fractionated and purified from the brown seaweed umitoranoo (Sargassum thunbergii) by fractional extraction, iron-exchange chromatography, and gel filtration. Thirty-one polysaccharide fractions were obtained and tested for antitumor activity in mice with Ehrlich carcinoma transplanted i.p. Two of the fractions, GIV-A ( – 127° and mol. wt., 19,000) and GIV-B ( – 110° and mol. wt., 13,500) had such activity. On the basis of chemical and spectral analyses, these compounds were found to be a fucoidan or L-fucan containing approx. 30% sulfate ester groups per fucose residue, about 10% uronic acid, and less than 2% protein.  相似文献   

2.
Protein-containing polysaccharides extracted from fruiting bodies of a Chinese fungus named Feng Wei Gu, were fractionated and purified, and their antitumor activities were tested, out of which the following active fractions were obtained.

FIo-a: A protein-containing xyloglucan, MW 280,000, polysaccharide: protein=76: 24 (w/w), polysaccharide consisting of Man: Gal: Xyl: Glc = 2: 12: 42: 42 (molar ratio). + 25.3°.

FA-2: A protein-containing mannogalactan, MW 120,000, polysaccharide: protein = 76 : 16 (w/w), consisting of Xyl : Man: Gal = 9 : 35 : 56 (molar ratio), + 98.5°.

FII-1: A Protein-containing xylan (62: 21 w/w). MW 200,000, +8.7°.

FIII-1a: A protein-containing glucoxylan (15: 71 w/w), +30.7°, MW 90,000, consisting of Glc : Xyl = 40 : 44 (molar ratio).

FIII-2a: A protein-containing xyloglucan, MW 70,000, polysaccharide: protein = 69: 3 (w /w), polysaccharide consisting of Xyl: Glc = 36 : 62 (molar ratio). + 38.6°.  相似文献   

3.
The substrate specificity of rice α-glucosidase II was studied. The enzyme was active especially on nigerose, phenyl-α-maltoside and maltooligosaccharides. The actions on isomaltose and phenyl-α-glucoside were weak, and on sucrose and methyl-α-glucoside, negligible. The α-glucans, such as soluble starch, amylopectin, β-limit dextrin, glycogen and amylose, were also hydrolyzed.

The ratio of the maximum velocities for hydrolyses of maltose (G2), nigerose (N), kojibiose (K), isomaltose (I), phenyl-α-maltoside (?M) and soluble starch (SS) was estimated to be 100: 94.4: 14.2: 7.1: 89.5: 103.1 in this order, and that for hydrolyses of malto-triose (G3), -tetraose (G4), -pentaose (G5), -hexaose (G6), -heptaose (G7), -octaose (G8), and amyloses ( and ), 113: 113: 113: 106: 113: 100: 106: 106. The Km values for N, K, I, ?M and SS were 2.4 mm, 0.58 mm, 20 mm, 1.6 mm and 5.0 mg/ml, respectively; those for G2, G3, G4, G5, G6, G7, G8, and , 2.4 mm, 2.2 mm, 2.1 mm, 1.5 mm, 1.0 mm, 1.1 mm, 0.95 mm, 1.5 mm and 1.1 mm.

Rice α-glucosidase II is considered an enzyme with a preferential activity on maltooligosaccharides.  相似文献   

4.
The behaviors of impurities on the crystallizations of the free acid and the hydrochloride, monosodium, zinc, calcium and barium salts of l-glutamic acid were examined, and a tendency was recognized that coexisting impurities were apt to be taken into the crystals when the crystallization proceeded from the zwitterion, i.e., Glu.± or The adsorption of l-tyro-sine was compared when l, d and dl-glutamic acid were crystallized with coexistence of l-tyrosine, and an effect of more or less extent of steric configuration on its behavior could be recognized.  相似文献   

5.
At maximum production of l-glutamic acid, the oxidation-reduction potential of the culture broth in l-glutamic acid fermentation showed a stable value of 9.0 to 9.6 as rH value. When biotin concentration in the medium was high (40γ/liter), the production of l-glutamic acid decreased, and the rH was 8.0 and it was out of accordance with that of the control (biotin-poor; 2γ/liter). Under “less-aerobic” conditions, its rH rose to 10.4.

From these results, it was concluded that the rH during maximum production of l-glutamic acid showed a stable value affected actively by the redox system, l-glutamic acid/α-ketoglutaric acid and   相似文献   

6.
Pseudomonas testosteroni ATCC 11996 was found to produce a novel bile acid sulfate sulfatase that hydrolyzes the sulfate ester bond in lithocholic acid sulfate (LCA-S). The enzyme synthesis was induced by several kinds of bile acids including LCA-S. Mn2+ functioned as an essential component for the enzyme synthesis and suppressed it. This sulfatase hydrolyzes LCA-S to isolithocholic acid and sulfuric acid with inversion of α- to β-configuration of the hydroxyl group at the third position of lithocholic acid.  相似文献   

7.
Radiolysis of some monosaccharides (fructose, glucose and ribose) in air-free condition was markedly enhanced by the addition of formate at concentrations above 20 mm, while it was inhibited at concentrations below 20 mm. The following compounds were detected in the irradiated sugar solutions containing excess formate (100mm): 1-Deoxy-d-arabinohexulose (1, G=4.4) and 1,3- dideoxy-d-erythrohexulose (2, G= 1.3) from fructose; 2-deoxy-d-ribose (3, G=2.3) and 2-deoxyribitol (4, G =0.6) from ribose; and 2-deoxy-d-glucose (5, G=0.5) and 2-deoxy-d-glucitol (6, G=0.4) from glucose. A mechanism for radiolytic formation of the products was proposed, based on interaction of - formed from formate with sugars.  相似文献   

8.
When 10?3m cysteine solution was irradiated in the presence of glucose at the concentration of ten-fold of cysteine, the G-values of products produced from cysteine were similar to those from 10?3m cysteine solution. On the other hand, the yield of carbonyl compound from glucose was suppressed completely by interaction between cysteine and radicals which are secondarily produced from glucose.

Methionine could not suppress the yield of carbonyl compound from glucose, and, G-values of products from methionine varied in comparison with those from solution containing methionine only.

From the results using scavenger, it was concluded that oxidation to methionine sulfoxide and cleavage to α-aminobutyric acid was caused by OH and attack, respectively.  相似文献   

9.
The d-xylose isomerase activity was assayed spectrophotometrically as NADH oxidation in a coupled reaction with the d-arabitol dehydrogenase. The assay system is based on the following reactions:

d-Arabitol dehydrogenase was purified from the d-sorbitol-grown cells of Agrobacterium tumefaciens. The standard assay condition is as follows: 5 μmoles of Tris-HCl buffer (pH 7.0), 0.2 μmole of MnCl2, 2 μl of reduced glutathione (25 mg/ml), 0.05 μmole of NADH, 6 units of d-arabitol dehydrogenase, 5 μmoles of d-xylose and d-xylose isomerase in a total volume of 0.30 ml. The reaction was carried out at 30°C. With the assay system, it was confirmed that d-xylose isomerase did not produce d-xylulose from d-lyxose.  相似文献   

10.
d-Glucose-isomerizing enzyme was purified in a crystalline form with a good yield from the cells of Bacillus coagulans, strain HN-68, and some phsicochemical properties were investigated.

The purified enzyme was homogeneous on both ultracentrifugal and disc-electrophoretical analyses. The molecular weight of the enzyme was determined to be 175,000 and 160,000 from the sedimentation-viscosity method and the gel filtration method, respectively.

The sedimentation coefficient , partial specific volume, at 280 mμ, and the nitrogen content of the enzyme were determined to be 10.2×10?13 sec, 0.705 cm3g?1, 10.6 and 16.2%, respectively. The integral numbers of amino acid residues per molecule calculated on the basis of 160,000 were as follows; Lys120, His49, Arg61, Asp182, Thr87, Ser70, Glu136, Pro44, Gly106, Ala140, Half-Cys0, Val53, Met27, Ileu51, Leu134, Tyr58, Phe96, Try13, and amide-ammonia80.

Purified enzyme preparation obtained from Bacillus coagulans, strain HN-68 requires Co2+ for d-glucose- and d-ribose-isomerizing activities and Mn2+ for d-xylose-isomerizing activity. The values of Km for d-glucose, d-xylose and d-ribose were 9×10?2, 1.1×10?3, 7.7×1O?m and of the relative Vmax were 0.52, 1.1 and 0.25 mg/min at 40°C, respectively. d-Glucose-isomerizing activity was inhibited by d-xylose and d-ribose. However, there was not a difference among three activities of the enzyme with respect to following properties: Activation energy was 14,600 cal per mol. The enzyme was inhibited in a competitive manner by tris(hydroxymethyl)aminomethane, d-xylitol, d-sorbitol and d-mannitol, and the Ki values for these inhibitor were 3×10?4, 2.5×10?3, 2.9×10?2 and 7×10?2m, respectively. The ratio of three activities did not change by heat- and pH-treatments. Mn2+, Co2+ and Ni2+ protected strongly the enzyme from heat denaturation. The enzyme can isomerize d-glucose, d-xylose and d-ribose to their corresponding ketose, but the kinetic constants and induction studies indicated that d-xylose is the natural substrate for the enzyme.  相似文献   

11.
Glucose is widely known to be required during superoxide generation in phagocytic cells. However, when an specific chemiluminescence probe with the Cypridina luciferin analog 2-methyl-6-(p-methoxyphenyl)-3, 7 -dihydroimidazo[ 1,2-a]pyrazin-3-one (MCLA) was used, about 60% of the chemiluminescence remained in stimulated macrophages in the presence of the glycolytic inhibitor 2-deoxyglucose. -nonspecific luminol-dependent chemiluminescence disappeared when the same drug was added. These results clearly demonstrate that the generation of by macrophages is not completely glucose-dependent, and strongly suggest that macrophages have both glucoseindependent NADPH-supplying pathway(s) and glucose dependent pathway(s) which generate reactive oxygen species other than .  相似文献   

12.
Malonogalactan, a malonylated polysaccharide (—74° (c=1.6, H2O)) produced by Penicillium citrinum, consisted of d-galactose and malonic acid in the approximate molar ratio of 3:1. Molecular weight of the demalonylated galactan (-99° (c=4.6, H2O)) was about 40,000. From the data regarding optical rotation, nuclear magnetic resonance spectrum, infrared spectrum, glycosidase susceptibility, periodate oxidation, Smith degradation, methylation and acid hydrolysis, the possible structure of the Penicillium malonogalactan is deduced as follows: A galactan, 1,5-β-galactofuranoside polymer esterified with malonic acid at the position of 2 or 3.  相似文献   

13.
The isolation of a new glycoside, named here as neocycasin A, with use of carbon chromatography, is described. It is one of a series of aliphatic azoxy glycosides, found in the seeds of Japanese cycad together with cycasin which is β-glucosyloxyazoxymethane as reported previously. The glycoside monohydrate gives m.p. 162° ~ 163° (decomp.), ? 35.1°; its heptaacetylate, m.p. 142° ~ 143°, ? 55.5°, from which octaacetyl-β-laminaribiose is isolated. On the basis of examination of the products obtained from partial or complete hydrolysis, and spectroscopic measurements, neocycasin A is concluded to be β-laminaribiosyloxyazoxymethane, i.e. 3-O-β-d-glucopyranosylcycasin.  相似文献   

14.
A crystalline alkaline protease was prepared from B. amylosacchariticus, which was isolated as a strain of saccharogenic α-amylase-producing Bacillus subtilis. The enzyme was most active at pH values between 10.3 and 10.7 towards casein and was stable at pH values from 6 to 11 on twenty hour incubation at 30°C. Calcium ions were effective to stabilize the enzyme especially at higher temperatures. The enzyme was markedly inactivated by DFP as well as protease inhibitor from potato and slightly by surface active agents, but not affected by sulfhydryl reagents and divalent metal ions except Hg++ .Hemoglobin was the best substrate for the enzyme and more than 20% of the peptide bonds were hydrolyzed. Of numerous synthetic peptides tested, only the two compounds, and , were found to be hydrolyzed. A cyclic peptide, gramicidin S, was split by the enzyme only at the peptide bond of -l-valyl-l-ornithyl-. Methyl n-butyrate and tributyrin were also good substrates for the alkaline protease obtained here.  相似文献   

15.
Molecular conformational transition of GDPMan and solution conformation of α-d- mannopyranose moiety in Man-l-P and GDPMan were examined in relation to other sugar nucleotides and phosphates. GDPMan and other sugar nucleotides examined revealed changes in the optical rotation in sigmoidal curve in water by addition of urea. The change was reversible without significant decomposition and is attributable to dissociation of an ordered form into a random form. Optical conformational values in 8m urea solution were+116° for GDPMan, +58°~+79° for UDPGlc, +79° for UDPGal, +135°~+143° for UDPGlcNAc, and +138°~ +155° for UDPGIcA.

NMR analysis and periodate oxidation study revealed the 4C1 conformation of α-d-hexopyranose moieties in Man-1-P, Glc-l-P, GDPMan, UDPGlcNAc and UDPGalNAc.  相似文献   

16.
Chemical investigations were made on a new unsaturated crystalline diuronide isolated from alginase hydrolysate of alginic acid. This uronide has (in water), and m.p. 135.5~136.5°C (decomp.). The presence of an α/β-unsaturated carboxylic acid formulation is supported by the following evidences: (a) an ultraviolet absorption band at 232 m/μ, (b) infrared absorption bands at 1648 cm-1 due to double bond and at 1720 cm-1 due to conjugated carboxylic group, (c) the consumption of about 1 mole of bromine per mole of the compound, (d) the production of oxalic acid on oxidation with ozone, (e) the formation of a substance that shows absorption maximum at 550 mμ, caused by the addition of thiobarbituric test. After hydrolysis, crystalline mannuronic lactone was obtained from the unsaturated diuronide. Occurrence of mannuronic moiety in the reducing unit was observed by paper chromatography of the hydrolysate of borohydride-reduced unsaturated compound. From these results it can be seen that the possible structure of this unsaturated diuronide is 4-O- (β-d-Δ4,5 mannoseenpyranosyluronic acid) -d-mannuronic acid.  相似文献   

17.
A polyuronide, main component of the water extract of achine of Ficus awkeotsang MAKINO (on-gyo-tye), was purified by ion-exchange chromatography on DEAE-cellulose. The polyuronide (Fraction IB) is homogeneous electrophoretically and consists mainly of galacturonic acid. Optical rotation of Fraction IB is and content of methoxyl group is trace. In periodate oxidation of Fraction IB, molar ratio of galacturonic acid residue and periodate consumption was 1, and formic acid formation was very small. Periodate oxidation product of Fraction IB was oxidized further with bromine and the resulted substance was hydrolyzed. In the hydrolyzate, presence of large amount of tartaric and glyoxylic acids and small amount of tartronic acid were detected by paper chromatography. Reduced viscosity of aquous solution of Fraction IB increased with decreasing of the concentration of Fraction IB solution. From these results, it was deduced that Fraction IB has a linear structure of 1→4 linkage of d-galacturonic acid, probably α-linkage.  相似文献   

18.
Crystalline tryptophanase prepared from the cells of Proteus rettgeri is inactive in the absence of added pyridoxal phosphate. Half-maximal enzyme activity is obtained at a concentration of 1.81 µm. Binding of pyridoxal phosphate to the apoenzyme is accompanied by pronounced increase in absorbance at 340 and 420 nm. Holotryptophanase requires K+ or for its maximal activity, but Na+ is inactive. No appreciable spectral change was observed on changing the ionic environments.

The amount of pyridoxal phosphate bound to the enzyme was determined by equilibrium dialysis and spectrophotometric titration to be 4 moles per mole of enzyme. Reduction of holoenzyme with sodium borohydride results in a shift of the absorption peak at 420 to 336 nm. ?-Pyridoxyllysine was isolated from the acid hydrolyzate of the reduced holoenzyme by paper chromatography and electrophoresis.

Addition of the substrate, l-tryptophan, or the competitive inhibitor, l-alanine, to the holoenzyme causes appearance of a new peak near 500 nm which disappears as the substrate is decomposed but remains unchanged in the presence of the inhibitor. The similar spectral change was observed by the addition of pyruvate, ammonia and indole to the holoenzyme.  相似文献   

19.
The effect of temperature and concentration on the relaxation of poly γ-benzyl-l-glutamate (PBLG-mol. wt. 394,000 to 397,000) was examined as a model of protein behavior under “stress” leading to the definition of intra- and inter-molecular forces involved. The relaxation of PBLG, unlike that of the random coil polymers, takes places in two stages. The lower the temperature and concentration of the polymer, the greater is the shift of the inflexion point towards the lower values.

The distribution spectrum of relaxation has a three zone characteristic. The possible significance of each of them is discussed.  相似文献   

20.
It has now been shown that Acetate A previously obtained by isomerizing ilexol acetate is nothing other than urs-13 (18)-en-3β-yl acetate prepared from α-amyrin, furnishing conclusive evidence for its conversion into one of the compounds of the ursane series.

Isoilexol, oxidized with chromium trioxide at room temperature, afforded a ketone named isoilexone, C30H48O, m.p. 194–195°, +75.90° (c, 0.527), and oxidized with the same oxidant at 70–80°, another ketone named isoilexenedione, C30H46O2, m.p. 221-223°, +16.28° (c, 0.307).

Huang-Milon reduction of these ketones afforded one and the same deoxy compound named isoilexene, C30H50, m.p. 183–185°, +48.34° (c, 0.290), which might well be assumed to constitute a pair of optical antipodes with olean-13 (18)-ene, C30H50, m.p. 184-185°, ?48.50° (c, 0.545).  相似文献   

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