Purification and properties of extracellular endoxylanases from alkalophilic thermophilic Bacillus sp.

1992 ◽  
Vol 38 (5) ◽  
pp. 436-442 ◽  
Author(s):  
Devyani Dey ◽  
Jyoti Hinge ◽  
Abhay Shendye ◽  
Mala Rao

An alkalophilic thermophilic Bacillus sp. (NCIM 59) isolated from soil produced two types of cellulase-free xylanase at pH 10 and 50 °C. The two enzymes (xylanase I and II) were purified to homogeneity by ethanol precipitation followed by Bio-Gel P-10 gel filtration and preparative polyacrylamide gel electrophoresis. The molecular weights of xylanase I and II were estimated to be 35 000 and 15 800, respectively, by sodium dodecyl sulfate gel electrophoresis. The enzymes exhibited immunological cross-reactivity and were glycoproteins. They had similar temperature (50–60 °C) and pH (6) optima. Both xylanases were stable at 50 °C at pH 7 for 4 days. However, xylanase I was comparatively more stable than xylanase II at 60 °C. The isoelectric points of xylanase I and II were 4 and 8, respectively. The apparent Km values, using xylan as substrate, were 1.58 and 3.5 mg/mL, and Vmax values were 0.0172 and 0.742 μmol∙min−1∙mg−1, respectively. Both xylanases were inhibited by N-bromosuccinimide, suggesting the involvement of tryptophan in the active site. The hydrolysis patterns demonstrated that the xylanases were endoenzymes. Xylanase I and II yielded mainly xylobiose, xylotriose, and higher xylooligosaccharides, with traces of xylose from xylan. Key words: cellulase-free xylanase, alkalophilic thermophilic Bacillus sp., enzyme purification, characterization.

1974 ◽  
Vol 77 (3) ◽  
pp. 485-497 ◽  
Author(s):  
P. A. Torjesen ◽  
T. Sand ◽  
N. Norman ◽  
O. Trygstad ◽  
I. Foss

ABSTRACT Highly purified human LH, FSH and TSH were isolated from batches of 300 frozen pituitary glands (200 g) by pH, acetone and ethanol fractionation, Sephadex gel filtration, ion-exchange chromatography on DEAE-cellulose and CM-Sephadex, and preparative polyacrylamide-gel electrophoresis. Sodium dodecyl-sulphate (SDS) polyacrylamide gel electrophoresis was used in order to check the purity, the identity and the molecular weight of the purified LH, FSH and TSH. This procedure showed that the hormone preparations consisted of two subunits with molecular weights of: LH: 21 300 and 17 900, FSH: 22 100 and 18 300 and TSH: 20 800 and 16 400. The purity of the hormone preparations was also evaluated by analytical disc electrophoresis at pH 8.9. The purified hormone preparations had radioimmunological activity as follows: LH: 20 000 IU/mg, FSH: 16 500 IU/mg and TSH: 5 IU/mg. All preparations had high biological potency.


1978 ◽  
Vol 171 (2) ◽  
pp. 435-444 ◽  
Author(s):  
D Propping ◽  
L J D Zaneveld ◽  
P F Tauber ◽  
G F B Schumacher

Two plasminogen activators (1 and 2) were isolated from human seminal plasma by hiigh-speed centrifugation, Sephadex-gel filtration and ion-exchange chromatography. The activators were shown to be homogeneous by polyacrylamide-disc -gel electrophoresis at pH 8.3 and 4.5, and by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. The molecular weights of activators 1 and 2 were estimated as 69 000 and 74 000. Their amino acid compositions are very similar, both being high in aspartic acid, glutamic acid, serine, glycine and leucine, and low in methionine, tryptophan, tyrosine, isoleucine and histidine. Activators 1 and 2 each possess 16 cysteine residues. Both activators have isoelectric points of approx. 7.0, are stable over a wide pH range at temperatures up to 60 degrees C, but lose activity at higher temperatures, particularly under very basic or acidic conditions. They are not inhibited by EDTA, Mg2+ and Ca2+ at 10 mM concentrations, but their activity decreases on addition of 10 mM-cysteine or Fe2+ and 6-aminohexanoate or sera from pregnant women. The precipitin band formed between urokinase and its antiserum is continuous with the precipitin bands formed between the seminal plasminogen activators and the urokinase antiserum. Antisera to urokinase inhibit both the activity of urokinase and the seminal plasminogen activators.


1977 ◽  
Vol 163 (1) ◽  
pp. 133-140 ◽  
Author(s):  
D V Marinkovic ◽  
J N Marinkovic

Hexosaminidase forms A and B were isolated from human kidney in a homogeneous state as demonstrated by electrophoretic and enzymic criteria. The enzymes were stable for at least 18 months when stored at -20 degrees C in 0.025 M-phosphate buffer, pH 6.5. The molecular weights of forms A and B were estimated by gel filtration to be 111 000 +/- 1500 and 114 000 +/- 1600 respectively. The molecular weights of hexosamidase A and B subunits were determined by using polyacrylamide-gel electrophoresis in the presence of sodium dodecyl sulphate. Hexosaminidase A dissociated into one subunit with mol.wt. 68 000. Hexosaminidase B dissociated into three subunits with mol. wts. 100 000, 68 000 and 37000 respectively, and one protein band of mol.wt. 140 000. After treatment of hexosaminidases A and B with iodoacetic acid, the molecular weights of the carboxymethylated polypeptide subunits were also estimated. Carboxymethylated hexosaminidase A dissociated into one major subunit of mol.wt. 18 000 and two other protein bands of mol.wts. 65 000 and 100 000. Carboxymethylated hexosaminidase B dissociated into one major subunit for mol.wt. 19 000 and an additional band of mol.wt. 37 000. The Km of the enzymes for the synthetic substrate p-nitrophenyl 2-acetamido-2-deoxy-beta-D-glucopyranoside was 0.8 mM. Both enzymes were inhibited or activated by various metal ions. Double pH optima for the enzymes were found at pH 4.5 and 4.8.


1985 ◽  
Vol 232 (1) ◽  
pp. 151-160 ◽  
Author(s):  
G J Hart ◽  
A R Battersby

Uroporphyrinogen III synthase (co-synthetase) purified from Euglena gracilis is a monomer of Mr 38 500 by gel-filtration studies and 31 000 by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. The pI is apparently in the range 4.8-5.1. No evidence for any cofactors was found, and folate derivatives were shown to be absent; no metal ions appear to be present in the enzyme. The Km for hydroxymethylbilane is in the range 12-40 microM, and the product, uroporphyrinogen III, is an inhibitor. Modification studies suggest that arginine residues are essential for the activity of co-synthetase; lysine residues may also be essential, but histidine, cysteine and tyrosine residues are not.


1980 ◽  
Vol 189 (1) ◽  
pp. 185-188 ◽  
Author(s):  
M J Prigent ◽  
R Bourrillon

The subunit of the Vicia graminea lectin with blood-group-N specificity was examined by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and gel filtration in 6M-guanidinium chloride, and its molecular weights was found to be 25 000. The unique N-terminal sequence fof the first nine residues of the lectin confirmed that Vicia lectin consists of four identical chains non-covalently linked. Finally the microheterogeneity of the lectin shown by analytical isoelectric focusing is discussed.


1999 ◽  
Vol 65 (8) ◽  
pp. 3470-3472 ◽  
Author(s):  
Giuliano Degrassi ◽  
Lasse Uotila ◽  
Raffaella Klima ◽  
Vittorio Venturi

ABSTRACT We purified an intracellular esterase that can function as anS-formylglutathione hydrolase from the yeastSaccharomyces cerevisiae. Its molecular mass was 40 kDa, as determined by gel filtration and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The isoelectric point was 5.0 by isoelectric focusing. The enzyme activity was optimal at 50°C and pH 7.0. The corresponding gene, YJLO68C, was identified by its N-terminal amino acid sequence and is not essential for cell viability. Null mutants have reduced esterase activities and grow slowly in the presence of formaldehyde. This enzyme may be involved in the detoxification of formaldehyde, which can be metabolized toS-formylglutathione by S. cerevisiae.


1976 ◽  
Vol 157 (2) ◽  
pp. 409-413 ◽  
Author(s):  
R K Airas ◽  
E A Hietanen ◽  
V T Nurmikko

Pantothenase (EC 3.5.1.22) from Pseudomonas fluorescens UK-1 was purified to homogeneity as judged by disc-gel electrophoresis and isoelectric focusing. The purification procedure consisted of four steps: DEAE-Sephadex chromatography, (NH4)2SO4 precipitation, hydroxyapatite chromatography and preparative polyacrylamide-gel electrophoresis. Gel filtration on Ultrogel AcA 34 was used to determine the molecular weight, and sodium dodecyl sulphate/polyacrylamide-gel electrophoresis to study the subunit molecular weight. The enzyme appeared to be composed of two subunits with mol.wts. of approx. 50000 each. The total mol.wt. of the enzyme was thus about 100000. The isoelectric point was 4.7 at 10 degrees C.


1980 ◽  
Vol 187 (1) ◽  
pp. 123-129 ◽  
Author(s):  
J T Powell

Lung is one of the organs of the rat with a particular abundance of haemagglutinating activity that is inhibited by beta-galactosides. This lectin activity can be attributed to a single protein that has been purified from rat lung; a similar protein has been purified from human lung. The molecular weights and subunit structures were estimated from gel filtration and sodium dodecyl sulphate/polyacrylamide-gel electrophoresis; the human lung lectin appeared to be composed to two identical subunits, mol.wt. 14500, whereas rat lung lectin was observed as both a dimer and a tetramer of one subunit type, mol.wt. 13500. Both lectins bind to disaccharides or oligosaccharides with terminal beta-linked galactose residues. The carbohydrate moiety may be free [lactose or D-galactopyranosyl-beta-(1 leads to 4)-thiogalactopyranoside], protein-bound (asialofetuin) or lipid-bound (cerebrosides). The molecular properties of the beta-galactoside-binding proteins of rat lung and human lung are closely similar to those of embryonic chick muscle lectin [Nowak, Kobiler, Roel & Barondes (1977) Proc. Natl. Acad. Sci. U.S.A. 73, 1383–1387] and calf heart lectin [De Waard, Hickman & Kornfeld (1976) J. Biol. Chem. 251, 7581–7587].


1975 ◽  
Vol 151 (3) ◽  
pp. 645-653 ◽  
Author(s):  
Z Werb ◽  
J J Reynolds

1. A specific collagenase from the culture medium of rabbit synovial fibroblasts was purified by gel filtration and ion-exchange chromatography. 2. The enzyme was homogenous on polyacrylamide-gel electrophoresis and showed only traces of contaminants when tested in gels with a non-specific antiserum. 3. The rabbit fibroblast collagenase could hydrolyse collagen both in solution and in fibrillar form. Viscometry showed that at 35°C the purified enzyme could hydrolyse >50 nmol of collagen/min per mg of enzyme. 4. The purified collagenase cleaved collagen in solution at either 24°or 35°C into the characteristic 1/4 and 3/4-length fragments. However, as compared with the impure enzyme, the purified enzyme at 35°C had a much decreased capacity to further degrade the initial specific cleavage products. 5. The specific rabbit collagenase had a mol. wt. of approx. 32000 as estimated by sodium dodecyl sulphate-polyacrylamide-gel electrophoresis, and 35000 by gel filtration.


1982 ◽  
Vol 47 (01) ◽  
pp. 014-018 ◽  
Author(s):  
H Sumi ◽  
N Toki ◽  
S Takasugi ◽  
S Maehara ◽  
M Maruyama ◽  
...  

SummaryPapain treatment of human urinary trypsin inhibitor (UTI67; mol. wt. 43,000 by SDS-polyacrylamide gel electrophoresis, specific activity 1,897 U/mg protein) produced four new protease inhibitors, which were highly purified by gel chromatography on Sephadex G-100 and isoelectric focusing. The purified inhibitors (UTI26, UTI9-I, UTI9-II, and UTI9-III) were shown to be homogeneous by polyacrylamide disc gel electrophoresis, and had apparent molecular weights of 26,000, 9,000, 9,000, and 9,800, respectively, by sodium dodecyl sulfate gel electrophoresis. During enzymatic degradation of UTI67, the amino acid compositions changed to more basic, and the isoelectric point increased from pH 2.0 (UTI67) to pHs 4.4, 5.2, 6.6, and 8.3 (UTI26, UTI9-I, UTI9-II, and UTI9-III), respectively. Both the parent and degraded inhibitors had anti-plasmin activity as well as antitrypsin and anti-chymotrypsin activities. Much higher anti-plasmin/anti-trypsin and anti-plasmin/anti-chymotrypsin activities were observed in the degraded inhibitors than in the parent UTI67. They competitively inhibited human plasmin with Ki values of 1.13 X 10-7 - 2.12 X 10-6 M (H-D-Val-Leu-Lys-pNA substrate). The reactions were very fast and the active site of the inhibitors to plasmin was thought to be different from that to trypsin or chymotrypsin.


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