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1.
Daneshfar A Ghaedi M Vafafard S Shiri L Sahrai R Soylak M 《Biological trace element research》2012,145(2):240-247
In this study, a solid-phase extraction method combined with atomic absorption spectrometry for extraction, preconcentration,
and determination of iron (Fe3+), copper (Cu2+), and lead (Pb2+) ions at trace levels in water samples has been reported. The influences of effective parameters such as flow rate, pH, eluent
conditions (type, volume, and concentration), sample volumes, and interference of matrix ions on metal ions recoveries were
studied. Under optimized conditions, the limits of detection were found in the range of 0.7–2.2 μg L−1, while preconcentration factors for Fe3+, Cu2+, and Pb2+ ions were found to be 166, 200, and 250, respectively, and loading half time (t
1/2) values were less than 2 min for all analyte ions. The proposed procedure was applied for the determination of metal ions
in different water samples with recovery of >94.4% and relative standard deviation less than 4.4% for N = 5. 相似文献
2.
Industrial wastewaters polluted with toxic heavy metals are serious ecological and environmental problem. Therefore, in this
study multi-heavy metals (Fe2+, Cu2+, Ni2+ and Zn2+) removal process with mixed microbial culture was examined in the horizontal rotating tubular bioreactor (HRTB) by different
combinations of process parameters. Hydrodynamic conditions and biomass sorption capacity have main impact on the removal
efficiency of heavy metals: Fe2+ 95.5–79.0%, Ni2+ 92.7–54.8%, Cu2+ 87.7–54.9% and Zn2+ 81.8–38.1%, respectively. On the basis of experimental results, integral mathematical model of removal heavy metals in the
HRTB was established. It combines hydrodynamics (mixing), mass transfer and kinetics to define bioprocess conduction in the
HRTB. Mixing in the HRTB was described by structured cascade model and metal ion removal by two combined diffusion–adsorption
models, respectively. For Langmuir model, average variances between experimental and simulated concentrations of metal ions
were in the range of 1.22–10.99 × 10−3 and for the Freundlich model 0.12–3.98 × 10−3, respectively. On the basis of previous facts, it is clear that developed integral bioprocess model with Freundlich model
is more efficient in the prediction of concentration of metal ions in the HRTB. Furthermore, the results obtained also pointed
out that the established model is at the same time accurate and robust and therefore it has great potential for use in the
scale-up procedure. 相似文献
3.
Mildred M. Rodriguez-Ramos Jonathan J. Wilker 《Journal of biological inorganic chemistry》2010,15(5):629-639
Modified oligonucleotides are showing potential for multiple applications, including drug design, nanoscale building blocks,
and biosensors. In an effort to expand the functionality available to DNA, we have placed chelating ligands directly into
the backbone of DNA. Between one and three nucleosides were replaced with 2,2′-bipyridine phosphates in 23-mer duplexes of
DNA. An array of metal ions were added (Fe2+, Co2+, Ni2+, Cu2+, Zn2+, and Pt2+) and the influences on duplex stability were examined by melting temperature studies. Titrations and UV–vis absorption spectroscopy
were used to provide insights into the nature of the metal complexes formed. We found that Ni2+ binding to 2,2′-bipyridine typically provided the greatest increase in duplex stability relative to the other metal ions
examined. For example, addition of Ni2+ to one 2,2′-bipyridine–DNA duplex increased the melting temperature by 13 °C, from 65.0 ± 0.3 to 78.4 ± 0.9 °C. These studies
show that metal ions and backbone ligands can be used to regulate DNA structure and stability. 相似文献
4.
Changes in the water permeability, aquaporin (AQP) activity, of leaf cells were investigated in response to different heavy
metals (Zn2+, Pb2+, Cd2+, Hg2+). The cell pressure probe experiments were performed on onion epidermal cells as a model system. Heavy metal solutions at
different concentrations (0.05 μM–2 mM) were used in our experiments. We showed that the investigated metal ions can be arranged
in order of decreasing toxicity (expressed as a decrease in water permeability) as follows: Hg>Cd>Pb>Zn. Our results showed
that β-mercaptoethanol treatment (10 mM solution) partially reverses the effect of AQP gating. The magnitude of this reverse
differed depending on the metal and its concentration. The time course studies of the process showed that the gating of AQPs
occurred within the first 10 min after the application of a metal. We also showed that after 20–40 min from the onset of metal
treatment, the water flow through AQPs stabilized and remained constant. We observed that irrespective of the metal applied,
the effect of AQP gating can be recorded within the first 10 min after the administration of metal ions. More generally, our
results indicate that the toxic effects of investigated metal ions on the cellular level may involve AQP gating. 相似文献
5.
Mohsen Mohamed Selim Asker Mohamed Fawzy Ramadan Samir Khalf Abd El-Aal Ebtsam Mokhtar Mohamed El-Kady 《World journal of microbiology & biotechnology》2009,25(5):789-794
Trehalose synthase (TSII) from Corynebacterium nitrilophilus NRC was successively purified by ammonium sulphate precipitation, ion exchange chromatography on DEAE-cellulose and gel filtration
chromatography on Sephadex G-100 columns. The specific activity of the trehalose synthase was increased ~200-fold, from 0.14
U mg−1 protein to 28.3 U mg−1 protein. TSII was found to be a monomeric protein with a molecular weight of 67–69 kDa. Characterization of the enzyme exhibited
optimum pH and temperature were 7.5 and 35°C, respectively. The purified enzyme was stable from pH 6.6 to 7.8 and able to
prolong its thermal stability up to 35°C. The enzyme activity was inhibited strongly by Zn2+, Hg2+ and Cu2+ and moderately by Ba2+, Fe2+, Pb2+ and Ni2+. Other metal ions Ca2+, Mg2+, Co2+, Mn2+ and EDTA had almost no effect. 相似文献
6.
Guo Li-Qiong Lin Shuo-Xin Zheng Xiao-Bing Huang Zi-Rou Lin Jun-Fang 《World journal of microbiology & biotechnology》2011,27(3):731-735
A thermostable laccase was isolated from a tropical white-rot fungus Polyporus sp. which produced as high as 69,738 units of laccase l−1 in an optimized medium containing 20 g of malt extract l−1, 2 g of yeast extract l−1, 1.5 mM CuSO4. The laccase was purified to electrophoretic purity with a final purification of 44.70-fold and a recovery yield of 21.04%.
The purified laccase was shown to be a monomeric enzyme with a molecular mass of 60 kDa. The optimum temperature and pH value
of the laccase were 75°C and pH 4.0, respectively, for 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonate) (ABTS). The Michaelis–Menten
constant (K
m
) of the laccase was 18 μM for ABTS substrate. The laccase was stable at pH values between 5.5 and 7.5. About 80% of the initial
enzyme activity was retained after incubation of the laccase at 70°C for 2 h, indicating that the laccase was intrinsically
highly thermostable and with valuable potential applications. The laccase activity was promoted by 4.0 mM of Mg2+, Mn2+, Zn2+ and Ca2+, while inhibited by 4.0 mM of Co2+, Al3+, Cu2+, and Fe2+, showing different profiles of metal ion effects. 相似文献
7.
Ming Xing Huang Yun Ye Ya Xiong Chen Ya Li Han 《International journal of peptide research and therapeutics》2012,18(2):153-161
Two proteins with fibrinolytic activity were partially purified from yellow mealworm (Tenebrio molitor) by ammonium sulfate precipitation between 30 and 70% saturation, gel filtration on Sephacryl-S200-HR, ion exchange chromatography
on DEAE-Sepharose-FF and metal chelate on Cu–HiTrap–IMAC–FF, but the enzymes had not been completely separated from each other.
The two partially purified fibrinolytic enzymes were designated as TMFE-I and TMFE-II (Tenebrio molitor fibrinolytic enzyme) with molecular weights of 27.5 and 24.9 kDa by SDS-PAGE individually. The partially purified solution
of TMFE-I and TMFE-II was considerably stable in the range of pH 5–10 and characterized by pH optimum of the enzymatic activity
at 8.0. Thermal stability of TMFE was excellent at 45°C and below. The K
M value was 0.26 mM for amidolysis of Bz–Arg–pNA. According to inhibitor analysis by fibrin plate method, phenylmethylsulfonyl
fluoride and tosyl-lysine chloromethyl ketone inactivated TMFE almost completely, but trans-(epoxysuccinyl)-l-leucylamino-4-guanidinobutane (E-64) and EDTA had little effect on their fibrinolytic activity. According to metal ion analysis
by fibrin plate method, the effect of metal ions on activity of TMFE showed a great difference. Na+, K+ and Zn2+ had little effect on the activity of TMFE. Mg2+ and Cu2+ showed inhibition effect on the fibrinolytic activity of TMFE, but Ca2+ increased the fibrinolytic activity of TMFE at final concentration varying from 0 to 30 mM. 相似文献
8.
C. Derrick QuarlesJr. R. Kenneth Marcus Julia L. Brumaghim 《Journal of biological inorganic chemistry》2011,16(6):913-921
Competitive binding of Fe3+, Cr3+, and Ni2+ to transferrin (Tf) was investigated at various physiological iron to Tf concentration ratios. Loading percentages for these
metal ions are based on a two M
n+ to one Tf (i.e., 100% loading) stoichiometry and were determined using a particle beam/hollow cathode–optical emission spectroscopy
(PB/HC-OES) method. Serum iron concentrations typically found in normal, iron-deficient, iron-deficient from chronic disease,
iron-deficient from inflammation, and iron-overload conditions were used to determine the effects of iron concentration on
iron loading into Tf. The PB/HC-OES method allows the monitoring of metal ions in competition with Fe3+ for Tf binding. Iron-overload concentrations impeded the ability of chromium (15.0 μM) or nickel (10.3 μM) to load completely
into Tf. Low Fe3+ uptake by Tf under iron-deficient or chronic disease iron concentrations limited Ni2+ loading into Tf. Competitive binding kinetic studies were performed with Fe3+, Cr3+, and Ni2+ to determine percentages of metal ion uptake into Tf as a function of time. The initial rates of Fe3+ loading increased in the presence of nickel or chromium, with maximal Fe3+ loading into Tf in all cases reaching approximately 24%. Addition of Cr3+ to 50% preloaded Fe3+–Tf showed that excess chromium (15.0 μM) displaced roughly 13% of Fe3+ from Tf, resulting in 7.6 ± 1.3% Cr3+ loading of Tf. The PB/HC-OES method provides the ability to monitor multiple metal ions competing for Tf binding and will
help to understand metal competition for Tf binding. 相似文献
9.
Summary The characteristics of bioflocculant MBF3-3 produced by Bacillus sp. BF3-3 were investigated here. MBF3-3 showed excellent flocculating activity on real and synthetic wastewaters, and consumed
a much lower dosage than that of the widely used polyaluminum chloride (PAC) when flocculating brewery wastewater. Except
Fe3+, metal ions, including Al3+, Mg2+, Ca2+, K+ and Na+, can stimulate the flocculating activity of MBF3-3 obviously, and the stimulating effects increased in the order: monovalent < bivalent < trivalent.
MBF3-3 was mainly composed of acidic polysaccharide (66.1%) and protein (29.3%), in which acidic polysaccharide was the main
effective flocculating component. OH and COO– groups may play a vital role in the flocculation of suspended particles. 相似文献
10.
Zhiqiang Wu Guoliang Jiang Peng Xiang Honglei Xu 《International journal of peptide research and therapeutics》2008,14(2):113-120
An anionic trypsin (TRY-EP) was purified from North Pacific krill (Euphausia pacifica) by ammonium sulfate precipitation, ion-exchange and gel-filtration chromatography. The purified enzyme was identified as
a trypsin by LC-ESI-MS/MS analysis. The relative molecular mass of TRY-EP was 33 kDa, with isoelectric point of 4.5. The histidine,
tryptophan, arginine, lysine, aspartic acid and glutamic acid residues were functional groups to TRY-EP. TRY-EP was activated
by Ca2+ and Mg2+ and inhibited by some heavy metal ions (Zn2+, Cu2+, Pb2+ and Hg2+), organic solvents (ethanol, glycerin, DMSO and acetone) and specific trypsin inhibitors (benzamidine, CEOM, SBTI and TLCK).
TRY-EP was active over a wide pH (6.0–11.0) and temperature (10–70°C) range, with optimum of pH 9.0 and 40–50°C. TRY-EP was
stable between pH 6.0 and 11.0 and below 30°C. Compared with some trypsins from the Temperate and Tropical Zone organisms,
TRY-EP and other trypsins from the Frigid Zone organisms have higher affinity to substrate and 2–42-fold physiological efficiency. 相似文献
11.
A highly selective sucrose isomerase (SIase) was purified to homogeneity from the cell-free extract of Erwinia rhapontici NX-5 with a recovery of 27.7% and a fold purification of 213.6. The purified SIase showed a high specific activity of 427.1 U mg−1 with molecular weight of 65.6 kDa. The K
m for sucrose was 222 mM while V
max was 546 U mg−1. The optimum pH and temperature for SIase activity were 6.0 and 30 °C, respectively. The purified SIase was stable in the
temperature range of 10–40 °C and retained 65% of the enzyme activity after 2 weeks’ storage at 30 °C. The SIase activity
was enhanced by Mg2+ and Mn2+, inhibited by Ca2+, Cu2+, Zn2+, and Co2+, completely inhibited by Hg2+ and Ag2+. The purified SIase was strongly inhibited by SDS, while partially inhibited by dimethylformamide, tetrahydrofuran, and PMSF.
Additionally, glucose and fructose acted as competitive inhibitors for purified SIase. 相似文献
12.
Wang Qian Fu Shi-Jun Sun Jian-Yi Weng Xiao-Yan 《World journal of microbiology & biotechnology》2011,27(5):1247-1253
A novel neutral phytase gene (phyC) from Bacillus licheniformis was cloned and expressed in Pichia pastoris under the control of AOX1 promoter. The gene is 1,146 bp in size and encodes a polypeptide of 381 amino acids. The recombinant PhyCm (rePhyCm), driven
by the Saccharomyces cerevisiae α-mating factor, was secreted into culture medium. After 0.5% methanol induction for 96 h, the activity of rePhyCm in culture
supernatant reached 0.23 U/ml. The optimum temperature and pH of purified rePhyCm were 60°C and 7.5, respectively. The rePhyCm
was stable in a wide pH range of 5.0–9.0, especially for alkaline pH. The residual activities of rePhyCm retained over 80%
after being incubated at pH 5.0–9.0, 37°C for 1 h in the presence of 1 mM CaCl2. Interestingly, supplemental Ca2+ upgraded both the thermostability and pH stability of rePhyCm. Substrate specificity of rePhyCm, effects of metal ions and
chemicals on phytase activity were also investigated in current study. 相似文献
13.
We have identified two types of invertases, one bound ionically and the other covalently to the particulate fraction in grains
of heat tolerant C 306 and heat susceptible WH 542 cultivars of wheat (Triticum aestivum L.). The cell walls contained a high level of invertase activity, of which 79.2–72.8% was extractable by 2 M NaCl and 14.9–21.1%
by 0.5% EDTA in C 306 and WH 542, respectively. The NaCl-released invertase constituted the predominant fraction. Using 5–100 mM
sucrose and pH range of 4.0–7.0, the apparent Michaelis constant (K
m, enzyme substrate affinity measure) of enzyme ranged from 5.73 to 16.06 mM for C 306 and from 6.08 to 19.86 mM for WH 542.
The V
max (maximum catalytic rate) values at these pH were higher in C 306 (0.63–11.04 μg sucrose hydrolysed min−1) than WH 542 (0.51–8.73 μg sucrose hydrolysed min−1). By employing photo-oxidation and by studying the effect of pH on K
m and V
max, the involvement of histidine and α-carboxyl groups at the active site of the enzyme was indicated. The two cultivars also
showed differential response in terms of thermodynamic properties of the enzyme i.e. energy of activation (E
a), enthalpy change (ΔH) and entropy change (ΔS). NaCl-released invertase showed differential response to metal ions in two cultivars suggesting their distinctive nature.
Mn2+, Cu2+, Hg2+, Mg2+, Zn2+ and Cd2+ were strong inhibitors in WH 542 as compared to C 306 while K+, Ca2+ were stimulators in both the cultivars. Overall the results suggest that genetic differences exist in wall bound invertase
properties of wheat grains as evident in its altered kinetic behaviour. 相似文献
14.
Divalent metal ions (Fe2+, Cu2+, Zn2+, Ni2+, and Mn2+) induced lipid oxidation in cooked, but not in raw fish. The extent of lipid oxidation, measured by the production of thiobarbituric
acid reactive substances (TBRS), was increased with higher concentrations of iron, zinc, and nickel, but was decreased with
increasing concentrations of copper and manganese. The natural products: ellagic acid, tannic acid, myricetin, and quercetin,
inhibited lipid oxidation in cooked fish. The enhanced lipid oxidation caused by cupric ions (103 pmol/100 g fish) was also inhibited by the natural products. The degree of inhibition in copper-treated fish, however, was
less than that in fish that had no added copper. The inhibition was concentration dependent. The antioxidative potency of
the various natural products was independent of the type of metal ion-induced lipid oxidation. Ellagic acid was the most potent
antioxidant (75.7–83.9%), followed by tannic acid (60.4–77.3%), myricetin (52.9–70.4%), and quercetin (32.6–44.2%). 相似文献
15.
Jeyaraman Vikramathithan Gali Nirmal kumar Pandurangan Muthuraman Kotteazeth Srikumar 《The protein journal》2010,29(7):481-486
A thermo stable xylanase was purified and characterized from the cladodes of Cereus pterogonus plant species. The enzyme was purified to homogeneity by ammonium sulfate (80%) fractionation, ion exchange and size exclusion
chromatography. The enzyme showed a final specific activity of 216.2 U/mg and the molecular mass of the protein was 80 KDa.
The optimum pH and temperature for xylanase activity were 5.0 and 80 °C, respectively,. With oat spelt xylan as a substrate
the enzyme yielded a Km value of 2.24 mg/mL and a Vmax of 5.8 μmol min−1 mg−1. In the presence of metal ions (1 mM) such as Co2+,Mn2+, Ni2+, Ca2+ and Fe3+ the activity of the enzyme increased, where as strong inhibition of the enzyme activity was observed with the use of Hg2+, Cd2+, Cu2+, while partial inhibition was noted with Zn2+ and Mg2+. The substrate specificity of the xylanase yielded maximum activity with oat spelt xylan. 相似文献
16.
The degradation of fluoroacetate by microorganisms has been established for some time, although only a handful of dehalogenases
capable of hydrolyzing the stable C–F bond have been studied. Pseudomonas fluorescens DSM 8341 was originally isolated from soil and readily degrades fluoroacetate, thus it was thought that its dehalogenase
might have some desirable properties. The enzyme was purified from cell-free extracts and characterised: it is a monomer of
32,500 Da, with a pH optimum of 8 and is stable between pH 4 and 10; its activity is stimulated by some metal ions (Mg2+, Mn2+ and Fe3+), but inhibited by others (Hg2+, Ag2+). The enzyme is specific for fluoroacetate, and the K
m
for this substrate (0.68 mM) is the lowest determined for enzymes of this type that have been investigated to date. 相似文献
17.
Yuzbasheva EY Yuzbashev TV Laptev IA Konstantinova TK Sineoky SP 《Applied microbiology and biotechnology》2011,89(3):645-654
The gene encoding homodimeric β-galactosidase (lacA) from Bacillus licheniformis DSM 13 was cloned and overexpressed in Escherichia coli, and the resulting recombinant enzyme was characterized in detail. The optimum temperature and pH of the enzyme, for both
o-nitrophenyl-β-d-galactoside (oNPG) and lactose hydrolysis, were 50°C and 6.5, respectively. The recombinant enzyme is stable in the range of pH 5 to 9 at
37°C and over a wide range of temperatures (4–42°C) at pH 6.5 for up to 1 month. The K
m values of LacA for lactose and oNPG are 169 and 13.7 mM, respectively, and it is strongly inhibited by the hydrolysis products, i.e., glucose and galactose.
The monovalent ions Na+ and K+ in the concentration range of 1–100 mM as well as the divalent metal cations Mg2+, Mn2+, and Ca2+ at a concentration of 1 mM slightly activate enzyme activity. This enzyme can be beneficial for application in lactose hydrolysis
especially at elevated temperatures due to its pronounced temperature stability; however, the transgalactosylation potential
of this enzyme for the production of galacto-oligosaccharides (GOS) from lactose was low, with only 12% GOS (w/w) of total sugars obtained when the initial lactose concentration was 200 g/L. 相似文献
18.
Mohd. Shukuri Mohamad Ali Chong Chai Yun Adam Leow Thean Chor Raja Noor Zaliha Raja Abdul Rahman Mahiran Basri Abu Bakar Salleh 《The protein journal》2012,31(3):229-237
A mutant of the lipase from Geobacillus sp. strain T1 with a phenylalanine to leucine substitution at position 16 was overexpressed in Escherichia coli strain BL21(De3)pLysS. The crude enzyme was purified by two-step affinity chromatography with a final recovery and specific
activity of 47.4 and 6,315.8 U/mg, respectively. The molecular weight of the purified F16L lipase was approximately 43 kDa
by 12% SDS-PAGE analysis. The F16L lipase was demonstrated to be a thermophilic enzyme due its optimum temperature at 70 °C
and showed stability over a temperature range of 40–60 °C. The enzyme exhibited an optimum pH 7 in phosphate buffer and was
relatively stable at an alkaline pH 8–9. Metal ions such as Ca2+, Mn2+, Na+, and K+ enhanced the lipase activity, but Mg2+, Zn2+, and Fe2+ inhibited the lipase. All surfactants tested, including Tween 20, 40, 60, 80, Triton X-100, and SDS, significantly inhibited
the lipolytic action of the lipase. A high hydrolytic rate was observed on long-chain natural oils and triglycerides, with
a notable preference for olive oil (C18:1; natural oil) and triolein (C18:1; triglyceride). The F16L lipase was deduced to
be a metalloenzyme because it was strongly inhibited by 5 mM EDTA. Moderate inhibition was observed in the presence of PMSF
at a similar concentration, indicating that serine residues are involved in its catalytic action. Further, the activity was
not impaired by water-miscible solvents, including methanol, ethanol, and acetone. 相似文献
19.
Aneta Monika Białkowska Hubert Cieśliński Karolina Maria Nowakowska Józef Kur Marianna Turkiewicz 《Archives of microbiology》2009,191(11):825-835
A psychrotrophic bacterium producing a cold-adapted β-galactosidase upon growth at low temperatures was classified as Arthrobacter sp. 20B. A genomic DNA library of strain 20B introduced into Escherichia coli TOP10F′ and screening on X-Gal (5-bromo-4-chloro-3-indolyl-β-d-galactopyranoside)-containing agar plates led to the isolation of β-galactosidase gene. The β-galactosidase gene (bgaS) encoding a protein of 1,053 amino acids, with a calculated molecular mass of 113,695 kDa. Analysis of the amino acid sequence
of BgaS protein, deduced from the bgaS ORF, suggested that it is a member of the glycosyl hydrolase family 2. A native cold-adapted β-galactosidase was purified
to homogeneity and characterized. It is a homotetrameric enzyme, each subunit being approximately 116 kDa polypeptide as deduced
from native and SDS–PAGE, respectively. The β-galactosidase was optimally active at pH 6.0–8.0 and 25°C. P-nitrophenyl-β-d-galactopyranoside (PNPG) is its preferred substrate (three times higher activity than for ONPG—o-nitrophenyl-β-d-galactopyranoside). The Arthrobacter sp. 20B β-galactosidase is activated by thiol compounds (53% rise in activity in the presence of 10 mM 2-mercaptoethanol),
some metal ions (activity increased by 50% for Na+, K+ and by 11% for Mn2+) and inactivated by pCMB (4-chloro-mercuribenzoic acid) and heavy metal ions (Pb2+, Zn2+, Cu2+). 相似文献
20.
Chellappan S Jasmin C Basheer SM Kishore A Elyas KK Bhat SG Chandrasekaran M 《Journal of industrial microbiology & biotechnology》2011,38(6):743-752
An alkaline protease from marine Engyodontium album was characterized for its physicochemical properties towards evaluation of its suitability for potential industrial applications.
Molecular mass of the enzyme by matrix-assisted laser desorption ionization-mass spectrometry (MALDI-MS) analysis was calculated
as 28.6 kDa. Isoelectric focusing yielded pI of 3–4. Enzyme inhibition by phenylmethylsulfonyl fluoride (PMSF) and aprotinin
confirmed the serine protease nature of the enzyme. K
m, V
max, and K
cat of the enzyme were 4.727 × 10−2 mg/ml, 394.68 U, and 4.2175 × 10−2 s−1, respectively. Enzyme was noted to be active over a broad range of pH (6–12) and temperature (15–65°C), with maximum activity
at pH 11 and 60°C. CaCl2 (1 mM), starch (1%), and sucrose (1%) imparted thermal stability at 65°C. Hg2+, Cu2+, Fe3+, Zn2+, Cd+, and Al3+ inhibited enzyme activity, while 1 mM Co2+ enhanced enzyme activity. Reducing agents enhanced enzyme activity at lower concentrations. The enzyme showed considerable
storage stability, and retained its activity in the presence of hydrocarbons, natural oils, surfactants, and most of the organic
solvents tested. Results indicate that the marine protease holds potential for use in the detergent industry and for varied
applications. 相似文献