Advances in Enzyme Research
ISSN / EISSN : 2328-4846 / 2328-4854
Published by: Scientific Research Publishing, Inc. (10.4236)
Total articles ≅ 74
Latest articles in this journal
Advances in Enzyme Research, Volume 09, pp 10-18; doi:10.4236/aer.2021.91002
Solid-state fermentation was carried out using mycelium powder of Aspergillus niger as substrate for the production of chitosanase of Streptomyces. Results of the experiments indicated that the optimal medium consisted of wheat bran and mycelium powder of Aspergillus niger with initial moisture content of 60% - 70%. The enzyme activity reached 41.33 U per gram dry medium after cultured for 5 days at 28°C - 30°C and an initial pH 6.5. Chitosanase was detected on the second day of incubation and had maximal activity at 5 days and decreased gradually within a 1 month period. Solid-state fermentation is maybe an economic alternative in the production.
Advances in Enzyme Research, Volume 09, pp 1-9; doi:10.4236/aer.2021.91001
The word “natto” originated from Japan, which was known as stinky bean, salt bean or silk bean in Chinese folk. Natto contains multiple functional components, including nattokinase, soybean isoflavone, γ-polyglutamic acid, vitamin K2, biogenic amines, SOD, small-molecule polypeptide, which has good preventive and curative effects for many diseases, such as cardiovascular and cerebrovascular diseases, hyperlipidemia, hypertension, menopausal symptoms and hypoimmunity. Along with the aging population in the world and China, it is urgent to improve the quality of life. It is necessary to enhance the understanding of natto-related knowledge, expand propaganda power, accept natto consciously and eat natto frequently, which is good for our health and helps our country to build a healthy and harmonious society. This review will descript the development, components, functions and prospects of natto, which help us to offer theoretical basis for promoting natto industry.
Advances in Enzyme Research, Volume 09, pp 19-35; doi:10.4236/aer.2021.92003
NADH-glutamate dehydrogenase (GDH) is active in human tissues, and is chromatographically purified, and studied because it participates in synthesizing glutamate, a neurotransmitter. But chromatography dissociates the GDH isoenzymes that synthesize nongenetic code-based RNA enzymes degrading superfluous mRNAs thereby aligning the cellular reactions with the environment of the organism. The aim was to electrophoretically purify human hexameric GDH isoenzymes and to characterize their RNA enzyme synthetic activity as in plants. The outcome could be innovative in chemical dependency diagnosis and management. Multi metrix electrophoresis including free solution isoelectric focusing, and through polyacrylamide and agarose gels were deployed to purify the redox cycle isoenzymes of laryngeal GDH, and to assay their RNA enzyme synthetic activities. The laryngeal GDH displayed the 28 binomial isoenzymes typical of higher organisms. Isoelectric focusing purification produced pure GDH. Redox cycle assays of the GDH isoenzymes produced RNA enzymes that degraded human stomach total RNA. In the reaction mechanism, the Schiff-base intermediate complex between α-ketoglutarate and GDH is the target of nucleophiles, resulting to the disruption of synthesis of glutamate, and RNA enzyme. The strongest nucleophiles are the psychoactive alkaloids of tobacco, cocaine, opium poppy, cannabis smoke because they are capable of reacting with GDH Schiff base intermediate to stimulate synthesis of aberrant RNA enzymes that degrade cohorts of mRNAs thereby changing the biochemical pathways and exacerbating drug overdose and chemical dependency. Electrophoretic purification, and characterization of the RNA enzyme synthetic activity set the forecourt for innovative application of GDH redox cycles in the diagnostic management of chemical dependency.
Advances in Enzyme Research, Volume 08, 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 08, 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 08, 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 08, 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 08, 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 07, 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.
Advances in Enzyme Research, Volume 07, pp 1-13; doi:10.4236/aer.2019.71001
Sulfatases which cleave sulfate esters in biological systems are key enzymes that deserve special attention due to their significant roles in organic sulfur (OS) mineralization and inorganic sulfur () release. In this study, in-vitro experiments were conducted to evaluate S bonded substrate hydrolysis by a commercially available arylsulfatase (EC 184.108.40.206) from Aerobacter aerogenes. The enzyme-substrate interactions were assessed to determine: 1) rate of hydrolysis, 2) catalytic efficiency, 3) thermal stability, and 4) optimal pH of this enzyme. Arylsulfatase exhibited substrate hydrolysis with a high affinity for p-nitrophenyl sulfate (potassium 4-nitrophenyl sulfate (pNPS)). The optimum activity for the enzyme was observed to occur at a pH of 7.1. The optimal temperature was 37°C but ranged from 35°C - 45°C. The apparent Km and Kcat of the enzyme for pNPS hydrolysis at the optimal pH, and temperature were determined to be 1.03 mM and 75.73 μM/min, respectively. This work defines the catalytic and kinetic properties of arylsulfatase (EC 220.127.116.11) and confirms the optimal conditions for sulfatase activity testing. The resulting information is useful in elucidating the contributions that individual enzymes have for specific reactions rather than relying on traditional total enzyme activity measurements.