共查询到20条相似文献,搜索用时 0 毫秒
1.
Hye-Young Lee Myo-Jeong Kim Jin-Sook Baek Hee-Seob Lee Hyun-Ju Cha Soo-Bok Lee Tae-Wha Moon Eun-Seong Seo Doman Kim Cheon-Seok Park Kwan-Hwa Park 《Journal of Molecular Catalysis .B, Enzymatic》2003,26(3-6):293-305
To develop a new transfer product of sucrose, sucrose was modified to maltosyl-sucrose using the transglycosylation activity of maltogenic amylase from Bacillus stearothermophilus (BSMA). The transglycosylation reaction was conducted with maltotriose and sucrose as the donor and acceptor, respectively. The presence of various sucrose transfer products was confirmed by thin layer chromatography (TLC) and high performance anion exchange chromatography (HPAEC). The sucrose transfer products were isolated by alkali-degradation followed by charcoal column chromatography using 20% (v/v) ethanol, then purified by ion exchange and Biogel P-2 gel permeation chromatographies. The structures of the major transfer products were determined to be 6G--maltosyl-sucrose (maltosyl-sucrose 1) and 6F--maltosyl-sucrose (maltosyl-sucrose 2) by LC-MS and 13C NMR. The mixture of maltosyl-sucrose 1 and 2 showed low sweetness, high hygroscopicity, low Maillard reactivity, and high acid and heat stability. Furthermore, it had an inhibitory effect on mutansucrase and water-insoluble glucan formation. These results indicated that the mixture of maltosyl-sucrose 1 and 2 is a suitable sugar substitute useful for various food products. 相似文献
2.
M. Guncheva D. Zhiryakova N. Radchenkova M. Kambourova 《Journal of Molecular Catalysis .B, Enzymatic》2007,49(1-4):88-91
The influence of nonionic surfactants on the activity of a novel thermostable lipase from Bacillus stearothermophilus MC7 was investigated with a view to its potential for synthesis of structured lipids. A large number of modifiers within a broad concentration range were applied. The activity of the enzyme was measured at a relatively high reaction temperature. Highest degree of activation was observed when PEG6000 was applied (up to 2.3-fold increase). Modification essentially changed the performance of the lyophilised preparations—they keep up to 80% of the activity of the native enzyme in the presence of a detergent against 30% in its absence. The effect of sorbitan esters (spans) and polyoxyethylene derivatives of sorbitan esters (tweens) on lipase MC7 was estimated, their HLB value varying within the interval 2.1–16.7. Tweens were strong inhibitors at higher concentrations. For all spans, excepting span 60, an increase of enzyme activity with concentration was observed. All studied additives slow down the process of thermal denaturation. Lipase preparations preserve more than 60% of their activity after 30-min incubation at 75 °C in the presence of tween 60 or PEG4000. 相似文献
3.
Purification and properties of thermostable lipase from a thermophilic Bacillus stearothermophilus MC 7 总被引:3,自引:0,他引:3
M. Kambourova N. Kirilova R. Mandeva A. Derekova 《Journal of Molecular Catalysis .B, Enzymatic》2003,22(5-6):307-313
Extracellular thermostable lipase produced by the thermophilic Bacillus stearothermophilus MC 7 was purified to 19.25-fold with 10.2% recovery. The molecular weight of the purified enzyme determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was shown to be 62 500 Da. The purified enzyme expressed maximum activity at 75–80 °C and its half life was 30 min at 70 °C. The Km and Vmax were calculated to be, respectively, 0.33 mM and 188 μM min−1 mg−1 with p-nitrophenyl palmitate (pNPP) as a substrate. Enzyme activity was inhibited by divalent ions of heavy metals, thiol and serine inhibitors, whereas calcium ion stimulated its activity. The most advantageous method for immobilization was found to be ionic binding to DEAE Cellulose. The enzyme was able to hydrolyze both soluble and insoluble emulsified substrates and was classified as a lipase, expressing some esterase activity as well. 相似文献
4.
Crystals of ribosomal protein L6 from Bacillus stearothermophilus suitable for high resolution structural studies have been obtained. Crystals are hexagonal with space group P6122 (or the enantiomorph P6522) and cell dimensions a = b = 72.7 Å, c = 124.9 Å. A search for heavy atom derivatives is in progress. 相似文献
5.
G.-J. Kim J.-H. Park D.-C. Lee H.-S. Ro H.-S. Kim 《Molecular & general genetics : MGG》1997,255(2):152-156
The gene coding for the thermostable d-hydantoinase from the thermophilic bacterium Bacillus stearothermophilus SD1 was cloned and its nucleotide sequence was completely determined. The d-hydantoinase protein showed considerable amino acid sequence homology (20–28%) with other hydantoinases and functionally
related allantoinases and dihydroorotases. Strikingly the sequence of the enzyme from B. stearothermophilus SD1 exhibited greater than 89% identity with hydantoinases from thermophilic bacteria. Despite the extremely high amino acid
homology among the hydantoinases from thermophiles, the C-terminal regions of the enzymes were completely different in both
sequence and predicted secondary structure, implying that the C-terminal region plays an important role in determining the
biochemical properties of the enzymes. Alignment of the sequence of the d-hydantoinase from B. stearothermophilus SD1 with those of other functionally related enzymes revealed four conserved regions, and five histidines and an acidic residue
were found to be conserved, suggesting a close evolutionary relationship between all these enzymes.
Received: 20 December 1996 / Accepted: 12 March 1997 相似文献
6.
Supachok Sinchaikul Boonyaras Sookkheo Suree Phutrakul Fu-Ming Pan Shui-Tein Chen 《Protein expression and purification》2001,22(3):388
An expression library was generated from a partial NcoI and HindIII digest of genomic DNA from the thermophilic bacterium, Bacillus stearothermophilus P1. The DNA fragments were cloned into the expression vector pQE-60 and transformed into Escherichia coli M15[EP4]. Sequence analysis of a lipase gene showed an open reading frame of 1254 nucleotides coding a 29-amino-acid signal sequence and a mature sequence of 388 amino acids. The expressed lipase was isolated and purified to homogeneity in a single chromatographic step. The molecular mass of the lipase was determined to be approximately 43 kDa by SDS-PAGE and mass spectrometry. The purified lipase had an optimum pH of 8.5 and showed maximal activity at 55°C. It was highly stable in the temperature range of 30–65°C. The highest activity was found with p-nitrophenyl ester-caprate as the synthetic substrate and tricaprylin as the triacylglycerol. Its activity was strongly inhibited by 10 mM phenylmethanesulfonyl fluoride and 1-hexadecanesulfonyl chloride, indicating that it contains a serine residue which plays a key role in the catalytic mechanism. In addition, it was stable for 1 h at 37°C in 0.1% Chaps and Triton X-100. 相似文献
7.
The complete amino acid sequence of the initiation factor IF3 from Bacillus stearothermophilus has been elucidated. This was achieved by splitting the protein with trypsin, Staphylococcus protease or cyanogen bromide. The amino acid sequence was determined by manual Edman degradation, using the DABITC/PITC double-coupling method. The IF3 molecule contains 171 amino acids and has an Mr of 19 677. The sequence was compared to the homologous molecule from Escherichia coli; about 50% of the amino acid residues were found to be identical. 相似文献
8.
Tomas Pink Klemens Langer Christoph Hotzy Margit Sara 《Journal of biotechnology》1996,50(2-3):189-200
The crystalline cell surface layer (S-layer) of Bacillus stearothermophilus PV72 shows hexagonal lattice symmetry and is composed of a single protein species with a molecular weight of 130000. For investigating the regulation of S-layer protein synthesis, Bacillus stearothermophilus PV72 was grown in continuous culture on synthetic PVIII- medium with glucose as carbon source at constant dilution rate of 0.3 h−1 at 57 ° C under different conditions and limitations. A complete outer S-layer and an S-layer protein pool sufficient for formation of about 70% inner S-layer was produced under carbon-limited growth. The inner S-layer results from an S-layer protein pool stored in the peptidoglycan-containing layer of whole cells which can emerge and assemble on the inner face of the rigid cell wall layer during the cell wall preparation procedure. Under oxygen-limited growth, only a complete outer S-layer but no S-layer protein pool was synthesized. Reduction of the methionine concentration of PVIII-medium from 100 to 10 mg l−1 led to a clear decrease in S-layer protein production and to an incomplete outer S-layer. During growth in the presence of excess glucose, S-layer protein synthesis was replaced by that of an exopolysaccharide matrix. After changing to carbon limitation again, the original level of S-layer protein synthesis was achieved after only four volume exchanges. Feeding of casein hydrolysate or aromatic or basic amino acids to the continuous culture induced an irreversible loss of S-layer protein synthesis after from five to ten volume exchanges. In contrast, addition of Gly, Ala, Val, Leu, Ile, Glu, Gln, Asp, Asn, Ser and Thr in different mixtures could significantly stimulate S-layer protein production. 相似文献
9.
10.
Sameera Al-Awadi M. Afzal S. Oommen 《The Journal of steroid biochemistry and molecular biology》2001,78(5)
When Bacillus stearothermophilus, a thermophilic bacterium isolated from the Kuwaiti desert, was incubated with exogenous progesterone for 24 h, three monohydroxylated metabolites were produced. 20α-Hydroxyprogesterone was the major metabolite produced in 60.8 relative percentage yield. The other two monohydroxylated metabolites were identified as 6β-hydroxyprogesterone and the rare 6α-hydroxyprogesterone in 21.0 and 13.6 relative percentage yields, respectively. A new metabolite 9,10-seco-4-pregnene-3,9,20-trione was isolated in 3.7 relative percentage yield. All metabolites were purified by preparative TLC and HPLC followed by their identification using 1H, 13C NMR and other spectroscopic data. 相似文献
11.
A thermophilic Bacillus sp. was isolated that secreted an extracellular, thermostable lipolytic enzyme. The enzyme was purified to 58 folds with
a specific activity of 9730 units/mg of protein and yield of 10% activity by ammonium sulphate precipitation, Phenyl Sepharose
chromatography, gel-permeation followed by Q Sepharose chromatography. The relative molecular mass of the protein was determined
to be 61 kDa by SDS-PAGE and approximately 60 kDa by gel permeation chromatography. The enzyme showed optimal activity at
60–65 ∘C and retained 100% activity after incubation at 60 ∘C and pH 8.0 for 1 h. The optimum pH was determined to be 8.5. It exhibited 50% of its original activity after 65 min incubation
at 70 ∘C and 23 min incubation at 80 ∘C. Catalytic function of lipase was activated by Mg++ (10 mM), while mercury (10 mM) inactivated the enzyme completely. No effect on enzyme activity was observed with trypsin
and chymotrypsin treatment, while 50% inhibition was observed with thermolysin. It was demonstrated that PMSF, SDS, DTT, EDTA,
DEPC, βME (100 mM each) and eserine (10 mM) inhibited the activity of the lipolytic enzyme. With p-nitrophenyl laurate as
a substrate, the enzyme exhibited a K
m
and V
max of 0.5 mM and 0.139 μM/min/ml. The enzyme showed preference for short chain triacylglycerol and hydrolyzes triolein at all
positions. In contrast to other thermostable Bacillus lipases, this enzyme has very low content of hydrophobic amino acids (22.58 %). Immunological studies showed that the active
site and antigen-binding site of enzyme do not overlap. 相似文献
12.
A thermostable, alkaline active xylanase was purified to homogeneity from the culture supernatant of an alkaliphilic Bacillus halodurans S7, which was isolated from a soda lake in the Ethiopian Rift Valley. The molecular weight and the pI of this enzyme were estimated to be around 43 kDa and 4.5, respectively. When assayed at 70 °C, it was optimally active at pH 9.0–9.5. The optimum temperature for the activity was 75 °C at pH 9 and 70 °C at pH 10. The enzyme was stable over a broad pH range and showed good thermal stability when incubated at 65 °C in pH 9 buffer. The enzyme activity was strongly inhibited by Mn2+. Partial inhibition was also observed in the presence of 5 mM Cu2+, Co2+ and EDTA. Inhibition by Hg2+ and dithiothreitol was insignificant. The enzyme was free from cellulase activity and degraded xylan in an endo-fashion. 相似文献
13.
14.
Davina de C.M Simoes David McNeill Bjorn Kristiansen Michael Mattey 《FEMS microbiology letters》1997,147(1):151-156
The molecular mass of esterases usually falls in the range of 20–160 kDa, although an esterase of 5.7 kDa from Candida lipolytica has been described. Three other enzymes smaller than 10 kDa have been reported, all of which were more thermostable than their higher molecular mass counterparts. This paper describes the purification of an extracellular esterase hydrolysing fluorescein dibutyrate from Bacillus stearothermophilus NCIMB 13335. The esterase had a molecular mass of 1.57 kDa when analysed by SDS-PAGE, gel filtration and MALDI-TOF spectrometry. This enzyme retained more than 90% of its activity after incubation at 90°C for 2 h. 相似文献
15.
Toshiki Moeichi Ryozaburo Irie Nobuhiro Yano Hiroshi Kembo 《Bioscience, biotechnology, and biochemistry》2013,77(1):66-69
dl-Threonine and dl-allothreonine showed a protective effect on various bacterial cells in the process of freeze-drying whereas l- and d-forms of them did not, probably owing to the difference in the physicochemical characteristics between l- (or d-) form and dl-form of the compounds in question. There was no difference in the protective activity between the optically active and inactive forms in the cases of serine, proline, tartaric acid and pyrrolidonecaboxylic acid. 相似文献
16.
Summary A chitinase produced by Bacillus licheniformis MB-2 isolated from Tompaso geothermal springs, Indonesia, was purified and characterized. The extracellular enzyme was isolated by successive hydrophobic interaction, anion exchange, and gel filtration chromatographies. The purified enzyme was a monomer with an apparent molecular weight of 67 kDa. The optimal temperature and pH of the enzyme were 70 °C and 6.0, respectively. It was stable below 60 °C for 2 h and over a broad pH range of 4.0–11.0 for 4 h. The enzyme was resistant to denaturation by urea (1 M), Tween-20 (1%) and Triton-X (1%), but unstable toward organic solvents such as dimethyl sulphoxide, DMSO, (5%) and polyethylene glycol, PEG, (5%) for 30 min. The enzyme hydrolysed colloidal chitin, glycol chitin, chitosan, and glycol chitosan. The first 13 N-terminal amino acids of the enzyme were determined as SGKNYKIIGYYPS, which is identical to those in chitinases from B. licheniformis and B. circulans. 相似文献
17.
Paula S-Pereira Alexandra Mesquita Jos C. Duarte Maria Raquel Aires Barros Maria Costa-Ferreira 《Enzyme and microbial technology》2002,30(7):519-933
A Bacillus subtilis strain isolated from a hot-spring was shown to produce xylanolytic enzymes. Their associative/synergistic effect was studied using a culture medium with oat spelts xylan as xylanase inducer. Optimal xylanase production of about 12 U ml−1 was achieved at pH 6.0 and 50°C, within 18 h fermentation. At 50°C, xylanase productivity obtained after 11 h in shake-flasks, 96,000 U l−1 h−1, and in reactor, 104,000 U l−1 h−1 was similar. Increasing temperature to 55°C a higher productivity was obtained in the batch reactor 45,000 U l−1 h−1, compared to shake-flask fermentations, 12,000 U l−1 h−1. Optimal xylanolytic activity was reached at 60°C on phosphate buffer, at pH 6.0. The xylanase is thermostable, presenting full stability at 60°C during 3 h. Further increase in the temperature caused a correspondent decrease in the residual activity. At 90°C, 20% relative activity remains after 14 min. Under optimised fermentation conditions, no cellulolytic activity was detected on the extract. Protein disulphide reducing agents, such as DTT, enhanced xylanolytic activity about 2.5-fold. When is used xylan as substrate, xylanase production decreased as function of time in contrast, with trehalose as carbon source, xylanase production in maintained constant for at least 80 h fermentation. 相似文献
18.
Summary A native B. stearothermophilus 5S RNA-protein complex was isolated. Homologous and hybrid 5S RNA-protein complexes could be reconstituted from B. stearothermophilus and E. coli 5S RNA and ribosomal proteins. The major proteins involved in these complexes are for the B. stearothermophilus system B-L5 and B-L22 and for the E. coli system E-L18 and E-L25. Furthermore, a two-dimensional electrophoresis pattern of B. stearothermophilus 50S proteins is presented.Paper No. 2 on Structure and Function of 5S RNA. Preceding paper is by Erdmann, V. A., Doberer, H. G., Sprinzl, M., Molec. gen. Genet. 114, 89–94 (1971). 相似文献
19.
Zhang Jianping Cai Jun Deng Yinyue Chen Yuehua Ren Gaixin 《Frontiers of Biology in China》2007,2(1):26-29
Bacillus cereus 58 (Bc58) is a UV-resistant wild type strain that has an ability to produce a sorrel pigment induced by L-tyrosine. The Fourier-transform
infrared (FT-IR) spectra and chemical tests of its pigment are similar to that of the standard melanin (Sigma). A bioassay
shows that the LC50 of a Bacillus thuringiensis (Bt) formulation added with the melanin of Bc58 and exposed to UV for 5 h is 16.1 μg/ml, which is similar to that of the
Bt formulation without UV treatment, however, it is almost double that of the Bt formulation exposed to UV without the melanin
of Bc58. The result of SDS-PAGE indicates that the melanin of Bc58 can protect the insecticidal crystal proteins from degradation.
This suggests that it is an excellent UV protective agent for the insecticidal crystal proteins of the Bt formulation.
Translated from Microbiology, 2006, 33(1): 42–45 [译自: 微生物学通报] 相似文献
20.
Amylases from adults of Sitophilus oryzae (L.) and S. granarius (L.) were purified by using a sequential procedure of ammonium sulfate precipitation, glycogen-complex formation, and ion exchange chromatography. Amylase of S. oryaze was purified 47.4-fold to a specific activity of 478 units/mg protein. One amylase unit equals 1 mg maltose hydrate produced/min at 30°C. Amylase of S. granarius was purified 85.4-fold to a specific activity of 453 units/mg protein. Amylase of S. oryzae had a Km of 0.173% for soluble starch and consisted of two anionic isozyrnes with isoelectric points of pH 3.70 and pH 3.76. Amylase of S. granarius had a Km of 0.078% for starch and was a single protein with an isoelectric point of pH 3.76. Purified amylases of both species had molecular weights of 56,000 estimated by sodium dodecyl sulfatepolyacrylamide gel electrophoresis, were activated by chloride, and had double energies of activation calculated from Arrhenius plots. Based on fresh weights of adults feeding on whole wheat through 10 weeks of age, S. oryzae contained three-fold and eight-fold more amylase than S. granarius and S. zeamais Motschulsky, respectively. High amylase levels in S. oryzae may provide this species with an adaptive advantage when feeding on cereals containing naturally occurring amylase inhibitors. 相似文献