Nε-Acetyl L-α Lysine Improves Activity and Stability of α-Amylase at Acidic Conditions: A Comparative Study with other Osmolytes

2020 ◽  
Vol 27 (6) ◽  
pp. 551-556
Author(s):  
Nidhya N. Joghee ◽  
Gurunathan Jayaraman ◽  
Masilamani Selladurai
Keyword(s):  
Enzyme Activity ◽  
Amino Acid ◽  
Thermodynamic Stability ◽  
Protective Effects ◽  
Residual Enzyme Activity ◽  
Functional Stability ◽  
Biotechnological Applications ◽  
Optimal Temperature ◽  
Acidic Conditions ◽  
Cellular Components

Background: Nε-acetyl L-α lysine is an unusual acetylated di-amino acid synthesized and accumulated by certain halophiles under osmotic stress. Osmolytes are generally known to protect proteins and other cellular components under various stress conditions. Objective: The structural and functional stability imparted by Nε-acetyl L-lysine on proteins were unknown and hence was studied and compared to other commonly known bacterial osmolytes - ectoine, proline, glycine betaine, trehalose and sucrose. Methods: Effects of osmolytes on the temperature and pH profiles, pH stability and thermodynamic stability of the model enzyme, α-amylase were analyzed. Results: At physiological pH, all the osmolytes under study increased the optimal temperature for enzyme activity and improved the thermodynamic stability of the enzyme. At acidic conditions (pH 3.0), Nε-acetyl L-α lysine and ectoine improved both the catalytic and thermodynamic stability of the enzyme; it was reflected in the increase in residual enzyme activity after incubation of the enzyme at pH 3.0 for 15 min by 60% and 63.5% and the midpoint temperature of unfolding transition by 11°C and 10°C respectively. Conclusion: Such significant protective effects on both activity and stability of α-amylase imparted by addition of Nε-acetyl L-α lysine and ectoine at acidic conditions make these osmolytes interesting candidates for biotechnological applications.

scholarly journals Primary structure requirements for correct sorting of the yeast mitochondrial protein ADH III to the yeast mitochondrial matrix space.

1987 ◽  
Vol 7 (1) ◽  
pp. 294-304 ◽  
Author(s):  
D Pilgrim ◽  
E T Young
Keyword(s):  
Amino Acids ◽  
Enzyme Activity ◽  
Amino Acid ◽  
Proteolytic Processing ◽  
Mitochondrial Matrix ◽  
Wild Type ◽  
Mature Form ◽  
Amino Terminal ◽  
The Matrix

Alcohol dehydrogenase isoenzyme III (ADH III) in Saccharomyces cerevisiae, the product of the ADH3 gene, is located in the mitochondrial matrix. The ADH III protein was synthesized as a larger precursor in vitro when the gene was transcribed with the SP6 promoter and translated with a reticulocyte lysate. A precursor of the same size was detected when radioactively pulse-labeled proteins were immunoprecipitated with anti-ADH antibody. This precursor was rapidly processed to the mature form in vivo with a half-time of less than 3 min. The processing was blocked if the mitochondria were uncoupled with carbonyl cyanide m-chlorophenylhydrazone. Mutant enzymes in which only the amino-terminal 14 or 16 amino acids of the presequence were retained were correctly targeted and imported into the matrix. A mutant enzyme that was missing the amino-terminal 17 amino acids of the presequence produced an active enzyme, but the majority of the enzyme activity remained in the cytoplasmic compartment on cellular fractionation. Random amino acid changes were produced in the wild-type presequence by bisulfite mutagenesis of the ADH3 gene. The resulting ADH III protein was targeted to the mitochondria and imported into the matrix in all of the mutants tested, as judged by enzyme activity. Mutants containing amino acid changes in the carboxyl-proximal half of the ADH3 presequence were imported and processed to the mature form at a slower rate than the wild type, as judged by pulse-chase studies in vivo. The unprocessed precursor appeared to be unstable in vivo. It was concluded that only a small portion of the presequence contains the necessary information for correct targeting and import. Furthermore, the information for correct proteolytic processing of the presequence appears to be distinct from the targeting information and may involve secondary structure information in the presequence.

scholarly journals Citrus polymethoxyflavones attenuate metabolic syndrome by regulating gut microbiome and amino acid metabolism

2020 ◽  
Vol 6 (1) ◽  
pp. eaax6208 ◽  
Author(s):  
Su-Ling Zeng ◽  
Shang-Zhen Li ◽  
Ping-Ting Xiao ◽  
Yuan-Yuan Cai ◽  
Chu Chu ◽  
...  
Keyword(s):  
Metabolic Syndrome ◽  
Amino Acid ◽  
Gut Microbiota ◽  
Metabolic Diseases ◽  
Amplicon Sequencing ◽  
Therapeutic Interventions ◽  
Protective Effects ◽  
Fecal Microbiome ◽  
Metabolomic Profiling ◽  
Branched Chain

Metabolic syndrome (MetS) is intricately linked to dysregulation of gut microbiota and host metabolomes. Here, we first find that a purified citrus polymethoxyflavone-rich extract (PMFE) potently ameliorates high-fat diet (HFD)–induced MetS, alleviates gut dysbiosis, and regulates branched-chain amino acid (BCAA) metabolism using 16S rDNA amplicon sequencing and metabolomic profiling. The metabolic protective effects of PMFE are gut microbiota dependent, as demonstrated by antibiotic treatment and fecal microbiome transplantation (FMT). The modulation of gut microbiota altered BCAA levels in the host serum and feces, which were significantly associated with metabolic features and actively responsive to therapeutic interventions with PMFE. Notably, PMFE greatly enriched the commensal bacterium Bacteroides ovatus, and gavage with B. ovatus reduced BCAA concentrations and alleviated MetS in HFD mice. PMFE may be used as a prebiotic agent to attenuate MetS, and target-specific microbial species may have unique therapeutic promise for metabolic diseases.

scholarly journals Protective Effects of 3-benzoyl-7-hydroxy Coumarin on Liver of Adult Rat Exposed to Aluminium Chloride

2021 ◽  
Vol 68 (1) ◽  
pp. 222-228
Author(s):  
Ahmet Özkaya ◽  
Kenan Türkan
Keyword(s):  
Oxidative Stress ◽  
Enzyme Activity ◽  
Aluminium Chloride ◽  
Control Group ◽  
Albino Rats ◽  
Activity Levels ◽  
Protective Effects ◽  
Adult Rat ◽  
Antioxidant Enzyme System ◽  
Hydroxy Coumarin

In this study, the effects of 3-benzoyl-7-hydroxy coumarin molecule on mineral and antioxidant enzymes were investigated in rat liver exposed to oxidative stress with aluminium chloride (AlCl3). Adult male Wistar albino rats were divided into four groups as Control, Coumarin, AlCl3, and Coumarin + AlCl3. Coumarin at the dose of 10 mg/kg and AlCl3 at the dose of 8.3 mg/kg were administered for 30 days every other day. In AlCl3 group, malondialdehyde (MDA), iron (Fe), aluminium (Al) and copper (Cu) levels increased compared to the control group, while glutathione (GSH) level, glutathione S-transferase (GST), and carboxylesterase (Ces) enzyme activity levels decreased. In Coumarin + AlCl3 group, MDA, Fe, Al and Cu levels decreased with the effect of coumarin compared to AlCl3 group, while GSH level, and GST enzyme activity levels increased. According to our results, AlCl3 generates oxidative stress in rat livers, and we believe that 3-benzoyl-7-hydroxy coumarin has an ameliorative effect on antioxidant enzyme system, Al, Fe and Cu levels.

scholarly journals Extruction of keratinase from the local isolate Bacillus licheniformis and partially purified and characterized

2009 ◽  
Vol 3 (2) ◽  
pp. 41-52
Author(s):  
Rasha T. Abdullah ◽  
Abdulkareem J. Hashim ◽  
JASIM M. Karhout
Keyword(s):  
Enzyme Activity ◽  
Bovine Serum Albumin ◽  
Ion Exchange ◽  
Bacillus Licheniformis ◽  
Enzyme Characterization ◽  
Optimal Temperature ◽  
Chicken Feathers ◽  
Local Isolate ◽  
Cellulose Column ◽  
Optimal Ph

The keratinase produced from local isolate Bacillus licheniformis was purified by two steps included precipitation by ammonium sulphate with 40% saturation; followed by ion exchange using CM-Cellulose column. The enzyme was purified to 12.6 times in the last step with an enzyme yield of 17%. Enzyme characterization results indicated that: The optimal pH for enzyme activity was 7.5 and it was stable at 7-9.5. The optimal temperature for enzyme activity was 50°C and it was stable for 30 min at 25-45 °C. Substrate specifity was tested using casein, Bovine serum albumin, gelatin, hooves, human hair, chicken feathers and wool; higher specifity was recorded using casein gave 0.6 unit /ml. The enzyme was inhibited by PMSF and metal ions like Hg+2, Fe+2, Cu+2 and Mn+2, and activated by Ca+2, Mg+2, Zn+2and Al+3.

scholarly journals Protective Effects of L-Theanine on IPEC-J2 Cells Growth Inhibition Induced by Dextran Sulfate Sodium Via p53 Signaling Pathway

Molecules ◽  
2021 ◽  
Vol 26 (22) ◽  
pp. 7002
Author(s):  
Longlin Zhang ◽  
Mengmeng Ma ◽  
Zhengyi Li ◽  
Haihan Zhang ◽  
Xi He ◽  
...  
Keyword(s):  
Amino Acid ◽  
Signaling Pathway ◽  
Dextran Sulfate ◽  
Dextran Sulfate Sodium ◽  
Nucleotide Metabolism ◽  
Normal Operation ◽  
Protective Effects ◽  
P53 Signaling ◽  
P53 Signaling Pathway

L-theanine is a nonprotein amino acid found in tea leaves and has been widely used as a safe food additive in beverages or foods because of its varied bioactivities. The aim of this study was to reveal the in vitro gastrointestinal protective effects of L-theanine in DSS-induced intestinal porcine enterocyte (IPEC-J2) cell models using molecular and metabolic methods. Results showed that 2.5% dextran sulfate sodium (DSS) treatment inhibited the cell proliferation of IPEC-J2 and blocked the normal operation of the cell cycle, while L-theanine pretreatment significantly preserved these trends to exert protective effects. L-theanine pre-treatment also up-regulated the EGF, CDC2, FGF2, Rb genes and down-regulated p53, p21 proliferation-related mRNA expression in DSS-treated cells, in accompany with p53 signaling pathway inhibition. Meanwhile, metabolomics analysis revealed that L-theanine and DSS treated IPEC-J2 cells have different metabolomic profiles, with significant changes in the key metabolites involved in pyrimidine metabolism and amino acid metabolism, which play an important role in nucleotide metabolism. In summary, L-theanine has a beneficial protection in DSS-induced IPEC-J2 cells via promoting proliferation and regulating metabolism disorders.

scholarly journals Two site-directed mutations abrogate enzyme activity but have different effects on the conformation and cellular content of the N-acetylgalactosamine 4-sulphatase protein

1995 ◽  
Vol 307 (2) ◽  
pp. 457-463 ◽  
Author(s):  
D A Brooks ◽  
D A Robertson ◽  
C Bindloss ◽  
T Litjens ◽  
D S Anson ◽  
...  
Keyword(s):  
Amino Acids ◽  
Enzyme Activity ◽  
Amino Acid ◽  
Cell Line ◽  
Protein Level ◽  
Structural Modification ◽  
Wild Type ◽  
Cellular Content ◽  
Control Protein ◽  
Wild Type Control

The sulphatase family of enzymes have regions of sequence similarity, but relatively little is known about either the structure-function relationships of sulphatases, or the role of highly conserved amino acids. The sequence of amino acids CTPSR at position 91-95 of 4-sulphatase has been shown to be highly conserved in all of the sequenced sulphatase enzymes. The cysteine at amino acid 91 of 4-sulphatase was selected for mutation analysis due to its potential role in either the active site, substrate-binding site or part of a key structural domain of 4-sulphatase and due to the absence of naturally occurring mutations in this residue in mucopolysaccharidosis type VI (MPS VI) patients. Two mutations, C91S and C91T, altering amino acid 91 of 4-sulphatase were generated and expressed in Chinese hamster ovary cells. Biochemical analysis of protein from a C91S cell line demonstrated no detectable 4-sulphatase enzyme activity but a relatively normal level of 4-sulphatase polypeptide (180% of the wild-type control protein level). Epitope detection, using a panel of ten monoclonal antibodies, demonstrated that the C91S polypeptide had a similar immunoreactivity to wild-type 4-sulphatase, suggesting that the C91S substitution does not induce a major structural change in the protein. Reduced catalytic activity associated with normal levels of 4-sulphatase protein have not been observed in any of the MPS VI patients tested and all show evidence of structural modification of 4-sulphatase protein with the same panel of antibodies [Brooks, McCourt, Gibson, Ashton, Shutter and Hopwood (1991) Am. J. Hum. Genet. 48, 710-719]. The loss of enzyme activity without a detectable protein conformation change suggests that Cys-91 may be a critical residue in the catalytic process. In contrast, analysis of protein from a C91T cell line revealed low levels of catalytically inactive 4-sulphatase polypeptide (0.37% of the wild-type control protein level) which had missing or masked epitopes, suggesting an altered protein structure or conformation. Subcellular fractionation studies of the C91T cell line demonstrated a high proportion of 4-sulphatase polypeptide content in organelles characteristic of microsomes. The aberrant intracellular localization and the reduced cellular content of 4-sulphatase polypeptide was consistent with the observed structural modification leading to retention and degradation of the protein within an early vacuolar compartment.

scholarly journals In Vivo Enzymes Activities of Some Ru(II) Compounds with N-Alkylphenothiazines

2016 ◽  
Vol 66 (4) ◽  
pp. 497-508
Author(s):  
P. Milena Krstić ◽  
Z. Sunčica Borozan ◽  
P. Sofija Sovilj ◽  
R. Sanja Grgurić-Šipka ◽  
M. Jelena Oljarević
Keyword(s):  
Antioxidant Activity ◽  
Enzyme Activity ◽  
Lactate Dehydrogenase ◽  
Normal Activity ◽  
Protective Effects ◽  
Toxic Compounds ◽  
Physiological Conditions ◽  
Positive Effects ◽  
Ldh Activity

Abstract The purpose of the present study was to investigate and compare the effects of two ruthenium complexes with trifluoperazine on acethylcholinesterase enzyme activity and lactate dehydrogenase levels in vivo under physiological conditions in rats blood. Complexes 1 and 2 showed positive effects on acethylcholinesterase at all doses and did not disturb its normal activity. Total LDH activity was inhibited in the presence of both complexes, but Ru(II) complexes showed different effects on the activity of LDH isoenzymes. The activities of LDH1 and LDH2 isoenzymes were decreased in all applied doses of the complex 2, while the activity of LDH2 reduced using complex 1 in the same doses. Results of the present study suggest the neuro- and cardio protective potential of oral administration of complexes 1 and 2, as non-toxic compounds under physiological conditions. These protective effects are the result of their potent antioxidant activity.

Production ofD-amino acid oxidase byAspergillussp. strain O20 active on cephalosporin C

1997 ◽  
Vol 43 (3) ◽  
pp. 292-295 ◽  
Author(s):  
Salim K. Mujawar ◽  
Jaiprakash G. Shewale
Keyword(s):  
Amino Acids ◽  
Enzyme Activity ◽  
Amino Acid ◽  
Stationary Growth Phase ◽  
Acid Oxidase ◽  
Cephalosporin C ◽  
Production Medium ◽  
Stationary Growth ◽  
Amino Acid Oxidase ◽  
Aspergillus Sp

Aspergillus sp. strain O20 produces inducible D-amino acid oxidase intracellularly, only in the presence of some amino acids. The enzyme was induced most effectively by the addition of DL-alanine (1% w/v) to the production medium. Among the various compounds studied, production of the D-amino acid oxidase was enhanced by Aerosol-22, glucose, and sodium nitrate. D-Amino acid oxidase formation was observed during the onset of the stationary growth phase. Maximum enzyme activity was recorded after 96 h of fermentation (1000 IU/L).Key words: D-amino acid oxidase, Aspergillus sp., 7-aminocephalosporanic acid, cephalosporin C.

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