Advances in Enzyme Research
ISSN / EISSN : 2328-4846 / 2328-4854
Current Publisher: Scientific Research Publishing, Inc. (10.4236)
Total articles ≅ 71
Latest articles in this journal
Advances in Enzyme Research, Volume 8, pp 49-57; doi:10.4236/aer.2020.84005
Chitosanases EAG1 is a classical glycoside hydrolase from Bacillus ehimensis. The previous researches showed that this Chitosanases can not only hydrolyze the b1,4-glycosidic bonds of chitosan to COS in different sizes but also keep a high catalytic activity in organic, which was useful for producing chitooligosaccharides and GlcN for use in the food and pharmacological industries. While it is instable in the liquid state. This shortcoming seriously restricts its industrial application. Here we used the modeled structure of EAG1 and the molecular modeling software package to screen the free chemical database ZINC. Moreover, the strategies including “initial filter” and consensus scoring were applied to accelerate the process and improve the success rate of virtual screening. Finally, five compounds were screened and they were purchased or synthetized to test their binding affinity against EAG1. The test results showed that one of them could inhibit the enzyme with an apparent Ki of 1.5 μM. The result may take the foundation for further inhibitor screening and design against EAG1 and the screened compound may also help to improve the liquid stability of EAG1 and expand its industrial application.
Advances in Enzyme Research, Volume 8, pp 1-18; doi:10.4236/aer.2020.81001
The medical herb Phyllanthus amarus play a crucial role in indigenous medicine. Therapeutically, these plants’ extract acts as potential players that inhibits several digestive enzymes that are relevant to the management of Peptic ulcers and Diabetes Mellitus, which occur due to the overproduction of such enzymes. Evaluation of inhibitory effect of this extract was carried out against Pepsin, α-amylase, Trypsin enzymes along with the effect of thermal stability and ammonium sulphate precipitation on these inhibitory assays. P. amarus leave’s extract with different concentration gradients were used in this research analysis. Results obtained along with the literature analysis revealed photochemical compounds such as polyphenols causes inhibitory nature in the extract. Maximal percentage of inhibition of amylase, pepsin and trypsin were found to be 71% (0.32 mg/ml), 85% (0.08 mg/ml) and 87% (1.28 mg/ml) respectively. In thermal stability assay the maximum percentage of inhibition for amylase, pepsin and trypsin was observed at 30% (80°C), 68% (4°C) and 5% (37°C). Enzymes inhibitory assays on ammonium sulphate precipitation elicited maximum percentage of inhibition for amylase, pepsin and trypsin as 42% (at 45% of (NH4)2SO4), 58% (at 15% of (NH4)2SO4) and 40% (at 30% of (NH4)2SO4) respectively. This research concluded that Phyllanthus amarus leave extracts are potential inhibitors of α-amylase, pepsin and trypsin enzymes. Ammonium sulphate precipitation was helpful to purify the polyphenols the active compounds to a good extend. Also, thermal stability was helpful to check the stability of these active photochemical compounds present in the extract. Thus, P. amarus is an effective inhibitor to be used as supplements in the disease management.
Advances in Enzyme Research, Volume 8, pp 39-48; doi:10.4236/aer.2020.84004
The aim of the present work was to isolate Bacillus spp. With high lipase activity; to characterize the isolates using both biochemical and molecular methods; to produce lipase using Bacillus isolates and to study the biochemical and biophysical characteristics of the produced lipase. Sixty five Bacillus isolates were isolated from soil 20 isolates from guar field soil (G), 15 isolates from Abusabein field soil (B), 15 isolates from sun flower field soil (S) and 15 isolates from oil effluent (O). Lipase producing isolates were screened; a Chromogenic plate’s method was used. Enzyme activity was quantitatively assayed. Lipase production under submerged fermentation (SMF) conditions using a production medium that contained metal salts, Tween-20 and olive oil as substrate at different period 24, 48, 72 and 96 h, the optimum pH, temperature for lipase activity was determinated and kinetics as well. The isolates showed the highest lipase activity which was identified as Bacillus sp. The optimum pH, temperature, thermostability and kinetic of the produced enzymes were found in three isolates G14, O1 and B10 with the highest enzyme activity and best stability. The isolates G14, O1 and B10 revealed the highest lipase activity of 63.4, 41.2 and 28.3 U/ml, respectively. The results showed optimum pH of the lipase activity from isolates G14, O1 and B10 8.0, 6.0 and 6.0 and the optimum temperature 40, 60 and 75˚C, respectively. Lipase enzymes from isolates O1 and B10 were found to be more thermostable after incubation time for 120 min at 90˚C. The Vmax and Km values of lipase for isolates G14, OI and B10 were 17.6, 135 and 24.4 μmole∙min and 1.3, 1.6 and 0.681 mM, respectively. According to these results Bacillus spp. with high lipase activity and thermostability can be used to promote food, pharmaceuticals, paper, detergents agrochemicals industries and pollution control in Sudan.
Advances in Enzyme Research, Volume 8, pp 27-37; doi:10.4236/aer.2020.83003
Combinatorial chemistry involves the chemical or biological synthesis of diverse variation of the structures of a target molecule and the library is then screened for variants of desirable target properties. The approach has been a focus of research activity in drug discovery and biotechnology. This report is to demonstrate the application of enzyme technology using the concept of combinatorial chemistry as a novel approach for the bioconversion of plant fibers. Wheat insoluble fiber was subjected to combinatorial enzyme digestion to create structural variants of feruloyl oligosaccharides (FOS). Fractionation and screening resulted in the isolation of a fraction of bioactive FOS species showing antimicrobial activity. These results demonstrate the feasibility and usefulness of the combinatorial enzyme technique in the transformation of plant biomass to value-added products.
Advances in Enzyme Research, Volume 8, pp 19-26; doi:10.4236/aer.2020.82002
Organomercury lyase (MerB) overexpressed in Escherichia coli captured and decomposed organomercury compounds, and it has been detected by radioactive analysis with neutron irradiation. Genetically modified E. coli captures a lot of mercury from a cultivation solution with about 80% recovery, when the bacteria are growing during 24 to 72 hours. Since the modified E. coli has no additive gene for mercury metabolism, the bacteria could hold mercury tightly by the MerB enzyme in their cell and do not release them into medium. In the later, 72 hours after, bacteria have less recovery ratio; it may be affected by undecompsed mercury compounds in bacteria growth. The recovery ability of the bacteria would not be changed by addition of the MerB producing reagent (IPTG). A quantitative value of mercury atom is estimated by an emission of γ-ray by reactor neutron from a dried cell or solution on a filter paper, which is available for nondestructive testing of bacteria holding mercury atoms. In this method an efficient recovery system of toxic mercury from a polluted solution has been archived without destruction of samples, so called in-cell analysis.
Advances in Enzyme Research, Volume 7, pp 45-56; doi:10.4236/aer.2019.74004
Proteases are important industrial enzymes that account for about 60% of the total enzyme market globally due to their large application in food, feed, textile and pharmaceutical industries. The effect of salt stress on protease production was evaluated on Aspergillus flavus and Aspergillus niger. The enzyme production was enhanced by stepwise optimization of the culture parameters, notably, carbon source, nitrogen source, pH, and temperature of the submerged fermentation process while using a minimal salt media and casein as substrate for the protease activity. The fungi species were found to be good producers of both acid and alkaline proteases under 4% salt stress condition. The optimum culture conditions for alkaline protease production by Aspergillus flavus were sucrose 4%, peptone 1%, pH 8 at 40°C with maximum enzymatic activities of 8.85 mM/min/mg protein, 5.22 mM/min/mg protein, 3.75 mM/min/mg protein, and 1.64 mM/min/mg protein, respectively. Lactose 4%, peptone 1%, pH 6 at 50°C were the optimum culture conditions for acid protease production by Aspergillus flavus with maximum enzymatic activities of 4.59 mM/min/mg protein, 2.06 mM/min/mg protein, 1.24 mM/min/mg protein, and 1.23 mM/min/mg protein, respectively. For Aspergillus niger, the optimum culture conditions for alkaline protease production were corn starch 4%, yeast extract 1%, pH 6 at 40°C with maximum enzymatic activities of 5.99 mM/min/mg protein, 3.85 mM/min/mg protein, 6.18 mM/min/mg protein, and 3.72 mM/min/mg protein, respectively. While lactose 4%, yeast extract 1%, pH 6 at 50°C were the best culture conditions for acid protease production by Aspergillus niger with maximum enzymatic activities of 4.81 mM/min/mg protein, 0.93 mM/min/mg protein, 5.71 mM/min/mg protein, and 3.34 mM/min/mg protein, respectively.
Advances in Enzyme Research, Volume 7, pp 1-13; doi:10.4236/aer.2019.71001
Advances in Enzyme Research, Volume 7, pp 57-65; doi:10.4236/aer.2019.74005
Phytase is a kind of enzyme that hydrolyzes phytic acid and its salts to produce inositol and phosphoric acid. As a new feed additive, phytase has great potential in animal nutrition and environmental protection. Because of its good stability, large-scale production and high activity, microbial phytase has become a hot spot in industrial application. Here, we reported the predicted structure and enzymatic properties of a phytase from Bacillus subtilis, which was named as phyS. It was clear that the optimal temperature is 35°C, and the optimal pH is 8. Meanwhile, the enzyme activity was kept at above 90% in the range of pH 8 - 9, this result demonstrated that phyS is an alkaline phytase. This study lays a foundation for the extensive application of phyS.
Advances in Enzyme Research, Volume 7, pp 27-44; doi:10.4236/aer.2019.73003
A conventionally synthesized thio- and cyano-modified single-stranded poly(dNTP) sequences of different molecular sizes (20n - 200n) and the same lengths routine poly(dNTP) and poly(NTP) species were obtained through the good services provided by the Russian Federal Bioorganic Products Group and by the ThermoFischer, Inc., and then tested for their impact on catalytic activities of β-like DNA polymerases from chromatin of HL-60, WERI-1A and Y-79 cells as well as for the affinity patterns in DNApolβ-poly(dNTP)/ (NTP) pairs, respectively. An essential link between the lengths of ultrashort (50n - 100n) single-stranded poly(dNTP) sequences of different structures and their inhibitory effects towards the cancer-specific DNA polymerases β has been found. A possible significance of this phenomenon for both DNA repair suppression in tumors and a consequent anti-cancer activity of the DNA repair related short poly(dNTP) fragments has been for the first time emphasized with a respect to their pharmacophore revealing potential. Thus, this work presents an experimental attempt to upgrade a contemporary attitude towards the DNA derived products applied for anti-cancer agenda, particularly, for acute myeloid leukemia and retinoblastoma cell DNA repair machinery breakdown. In this study, tumor specific DNA polymerases β were found of being the targets for attack promoted with the primer-like single-stranded DNA fragments followed by consequent cytostatic phenomena. A novel concept of the DNA related anti-cancer medicines is under discussion.
Advances in Enzyme Research, Volume 7, pp 15-25; doi:10.4236/aer.2019.72002
We screened 15 Agromyces strains from the Microbacteriaceae family and 16 Gordonia strains from the Gordoniaceae family to investigate their biocatalytic ability to reduce carbonyl compounds. Two Agromyces strains (A. soli NBRC109063 and A. humatus NBRC109085) and two Gordonia strains (G. hydrophobica NBRC16057 and G. malaquae NBRC108250) grew well in 230 medium. The stereoselective reduction of various carbonyl compounds using these four strains was investigated. We discovered that these strains can reduce aliphatic and aromatic α-keto esters and an aromatic α-keto amide. On the basis of the conversion rate and stereoselectivity of the alcohols produced, G. hydrophobica NBRC16057 is a potential biocatalyst for the stereoselective reduction of α-keto esters and an aromatic α-keto amide to the corresponding chiral alcohols. Our results also suggest that the reduction of ethyl 2-methylacetoacetate by wet G. hydrophobica NBRC16057 cells in the presence of L-glutamate is useful for the production of chiral ethyl 3-hydroxy-2-methylbutanoate.