The structures and activities of enzymes are influenced by pH of the environment. Understanding and distinguishing the adaptation mechanisms of enzymes to extreme pH values is of great significance for elucidating the molecular mechanisms and promoting the industrial applications of enzymes. In this study, the ESM-2 protein language model was used to encode the secreted microbial proteins with the optimal performance above pH 9 and below pH 5, which yielded 47 725 high-pH protein sequences and 66 079 low-pH protein sequences, respectively. A deep learning model was constructed to identify protein acid-base tolerance based on amino acid sequences. The model showcased significantly higher accuracy than other methods, with the overall accuracy of 94.8%, precision of 91.8%, and a recall rate of 93.4% on the test set. Furthermore, we built a website (https://enzymepred.biodesign.ac.cn), which enabled users to predict the acid-base tolerance by submitting the protein sequences of enzymes. This study has accelerated the application of enzymes in various fields, including biotechnology, pharmaceuticals, and chemicals. It provides a powerful tool for the rapid screening and optimization of industrial enzymes.
Deep Learning ; Hydrogen-Ion Concentration ; Amino Acid Sequence ; Enzymes/metabolism* ; Sequence Analysis, Protein ; Proteins/metabolism* ; Bacterial Proteins/metabolism*

OBJECTIVE: To develop a fast, sensitive and cost-effective method based on resonance light scattering (RLS) for characterization of protein solubility to facilitate detection of changes in solubility of mutant proteins. METHODS: We examined the response curve of RLS intensities to the protein concentrations in synchronous scanning mode. The curve intersection points were searched to predict the maximal concentrations of the protein in dispersion state, which defined the solubility of the protein in this given state. Bovine serum albumin (BSA, 0-50 g/L) was used as the model to investigate the influences of pH values (6.5, 7.0, and 7.4) and salt concentrations (0.05, 0.10, 0.15, and 0.20 mol/L) on the determined solubility. The solubility of glutathione S-transferase isoenzymes alpha (GSTA, 0-27.0 g/L) and Mμ (GSTM, 0-20.0 g/L) were estimated for comparison. The RLS-based method was used to determine the solubility of uricase (MGU, 0-0.4 g/L) to provide assistance in improving the solubility of its mutants. RESULTS: We identified two intersection points in the RLS response curves of the tested proteins, among which the lower one represented an approximation of the maximal concentration (or the solubility of the protein) in single molecular dispersion, and the higher one the saturated concentration of the protein in multiple molecular aggregation. In HEPES buffer, the two intersection points of BSA (isoelectric point 4.6) both increased with the increase of pH (6.5-7.4), and their values were ~1.2 g/L and ~33 g/L at pH 7.4, respectively; the latter concentration approached the solubility of commercial BSA in the same buffer at the same pH. The addition of NaCl reduced the values of the two intersection points, and increasing salt ion concentration decreased the values of the lower intersection points. Further characterizations of GSTA and GSTM showed that the low concentration intersection points of the two proteins were ~0.7 g/L and ~0.8 g/L, and their high concentration intersection points were ~10 g/L and ~11 g/L, respectively, both lower than those of BSA, indicating the feasibility of the direct characterization of protein solubility by RLS. The two concentration intersection points of MGU were 0.24 g/L and 0.30 g/L, respectively, and the low concentration intersection point of its selected mutant was increased by 2 times. CONCLUSIONS RLS allows direct characterization of the solubility of macromolecular proteins. This method, which is simple and sensitive and needs only a small amount of proteins, has a unique advantage for rapid comparison of solubility of low-abundance protein mutants.
Hydrogen-Ion Concentration ; Light ; Scattering, Radiation ; Solubility ; Spectrum Analysis

Adult ; Chromatin ; DNA Fragmentation ; Humans ; Hydrogen-Ion Concentration ; Infertility, Male ; Male ; Middle Aged ; Multivariate Analysis ; Principal Component Analysis ; Semen Analysis/methods* ; Sperm Count ; Sperm Motility ; Spermatozoa/metabolism*

We prepared a polymorphic form of valnemulin hydrogen tartrate (Form I) to overcome the instability and irritating odor of valnemulin hydrochloride that affect its use in the production and application of veterinary drugs. The physicochemical properties of Form I were characterized by scanning electron microscopy, X-ray powder diffraction, infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. The results showed the crystal structure and thermal properties of Form I were very different from those of a commercially available form of valnemulin hydrogen tartrate (Form II). Form I and Form II were more stable than valnemulin hydrochloride after storage under irradiation and high humidity conditions, respectively. The solubility of Form I was 2.6 times that of Form II, and Form I was selected for use in pharmaceutical kinetics experiments in vivo. Compared to valnemulin hydrochloride, after oral administration at a dose of 10 mg/kg in pigs, Form I had similar pharmaceutical kinetic behavior but a slightly higher area under the concentration–time curve from time zero to the last measurable concentration. Consequently, Form I should be suitable for the development of simple formulations and be effective in the clinical application of veterinary drugs.
Administration, Oral ; Calorimetry, Differential Scanning ; Humidity ; Hydrogen ; Kinetics ; Microscopy, Electron, Scanning ; Odors ; Pharmacokinetics ; Powder Diffraction ; Solubility ; Spectrum Analysis ; Swine ; Veterinary Drugs

BACKGROUND: The left internal thoracic artery (LITA) has been used as the first conduit of choice in coronary artery bypass grafting (CABG) because of excellent long-term patency and outcomes. However, no studies have examined substances other than nitric oxide that could be beneficial for the bypass conduit, native coronary artery or ischemic myocardium. This study was conducted to evaluate differences in metabolic profiles between the LITA and ascending aorta using gas chromatography-time of flight-mass spectrometry (GC-TOF-MS). METHODS: Twenty patients who underwent CABG using the LITA were prospectively enrolled. Plasma samples were collected simultaneously from the LITA and ascending aorta. GC-TOF-MS based untargeted metabolomic analyses were performed and a 2-step volcano plot analysis was used to identify distinguishable markers from two plasma metabolome profiles. Semi-quantitative and quantitative analyses were performed using GC-TOF-MS and enzyme-linked immunosorbent assay, respectively, after selecting target metabolites based on the metabolite set enrichment analysis. RESULTS: Initial volcano plot analysis demonstrated 5 possible markers among 851 peaks detected. The final analysis demonstrated that the L-cysteine peak was significantly higher in the LITA than in the ascending aorta (fold change = 1.86). The concentrations of intermediate metabolites such as L-cysteine, L-methionine and L-cystine in the ‘cysteine and methionine metabolism pathway' were significantly higher in the LITA than in the ascending aorta (2.0-, 1.4- and 1.2-fold, respectively). Quantitative analysis showed that the concentration of hydrogen sulfide (H2S) was significantly higher in the LITA. CONCLUSION: The plasma metabolome profiles of the LITA and ascending aorta were different, particularly higher plasma concentrations of L-cysteine and H2S in the LITA.
Aorta ; Chromatography, Gas ; Coronary Artery Bypass ; Coronary Vessels ; Cysteine ; Cystine ; Enzyme-Linked Immunosorbent Assay ; Humans ; Hydrogen Sulfide ; Mammary Arteries ; Mass Spectrometry ; Metabolism ; Metabolome ; Metabolomics ; Methionine ; Myocardium ; Nitric Oxide ; Plasma ; Prospective Studies ; Spectrum Analysis

β-Glucosidase activity assays constitute an important indicator for the early diagnosis of neonatal necrotizing enterocolitis and qualitative changes in medicinal plants. The drawbacks of the existing methods are high consumption of both time and reagents, complexity in operation, and requirement of expensive instruments and highly trained personnel. The present study provides a simplified, highly selective, and miniaturized glucometer-based strategy for the detection of β-glucosidase activity. Single-factor experiments showed that optimum β-glucosidase activity was exhibited at 50 °C and pH 5.0 in a citric acid-sodium citrate buffer when reacting with 0.03 g/mL salicin for 30 min. The procedure for detection was simplified without the need of a chromogenic reaction. Validation of the analytical method demonstrated that the accuracy, precision, repeatability, stability, and durability were good. The linear ranges of β-glucosidase in a buffer solution and rat serum were 0.0873-1.5498 U/mL and 0.4076-2.9019 U/mL, respectively. The proposed method was free from interference from β-dextranase, snailase, β-galactosidase, hemicellulase, and glucuronic acid released by baicalin. This demonstrated that the proposed assay had a higher selectivity than the conventional dinitrosalicylic acid (DNS) assay because of the specificity for salicin and unique recognition of glucose by a personal glucose meter. Miniaturization of the method resulted in a microassay for β-glucosidase activity. The easy-to-operate method was successfully used to detect a series of β-glucosidases extracted from bitter almonds and cultured by Aspergillus niger. In addition, the simplified and miniaturized glucometer-based assay has potential application in the point-of-care testing of β-glucosidase in many fields, including medical diagnostics, food safety, and environmental monitoring.
Animals ; Aspergillus niger ; Calibration ; Cellulase/analysis* ; Chemistry, Clinical/methods* ; Dextranase/analysis* ; Enterocolitis, Necrotizing/diagnosis* ; Equipment Design ; Flavonoids/analysis* ; Glucose/analysis* ; Glucuronic Acid/analysis* ; Glucuronidase/analysis* ; Glycoside Hydrolases/analysis* ; Hydrogen-Ion Concentration ; Linear Models ; Multienzyme Complexes/analysis* ; Plants, Medicinal ; Polygalacturonase/analysis* ; Rats ; Reproducibility of Results ; beta-Galactosidase/analysis* ; beta-Glucosidase/analysis*

The increasing demand of Chinese materia medica could not be supplied by wild resource, and the cultivated medicinal materials become popular, which led to decreased quality of many medicinal materials due to the difference of the circumstance between the wild and the cultivated. How to improve quality becomes key points of Chinese medicine resource. The leaves of Scutellaria baicalensis were sprayed with H₂O₂, the activities of superoxide dismutase (SOD) and catalase (CAT) changed little, but there had been a marked decrease of peroxidase (POD) and ascorbic oxidase (APX), which showed that the antioxidase system declined. Meanwhile, H₂O₂, as enhanced the expression of phenylalnine ammonialyase (PAL) and β-glucuronidase (GUS) as well as activity of PAL, promoted the biosynthesis and biotransformation of flavonoids. At the day 2 after treated, H₂O₂ of 0.004 μmol·L⁻¹ the contents of the baicalin and the wogonoside decreased slightly, but the contents of the baicalein and the wogonin increased significantly, the baicalein from 0.094% to 0.324%, the wogonin from 0.060% to 0.110%, i. e. increased 246% and 83.3%, respectively.
Ascorbate Oxidase ; metabolism ; Catalase ; metabolism ; Drugs, Chinese Herbal ; chemistry ; Flavanones ; analysis ; Flavonoids ; analysis ; Glucosides ; analysis ; Glucuronidase ; metabolism ; Hydrogen Peroxide ; Peroxidase ; metabolism ; Phenylalanine Ammonia-Lyase ; metabolism ; Scutellaria baicalensis ; metabolism ; Secondary Metabolism ; Superoxide Dismutase ; metabolism

A magnetic metal organic framework (MMOF) was synthesized and used to separate Sr2+ in aqueous solution. The shape and structure of prepared Fe3O4@UiO-66-NH2 were characterized, and the absorbed concentration of strontium was determined through inductively coupled plasma mass spectrometry. The results indicated that Fe3O4 and UiO-66-NH2 combined through chemical bonding. The experimental adsorption results for separation of Sr2+ in aqueous solution indicated that the adsorption of Sr2+ to Fe3O4@UiO-66-NH2 increased drastically from pH 11 to pH 13. The adsorption isotherm model indicated that the adsorption of Sr2+ conformed to the Freundlich isotherm model (R2 = 0.9919). The MMOF thus inherited the superior qualities of magnetic composites and metal organic frameworks, and can easily be separated under an external magnetic field. This MMOF thus has potential applications as a magnetic adsorbent for low level radionuclide 90Sr.
Adsorption ; Ferrosoferric Oxide ; chemistry ; Hydrogen-Ion Concentration ; Metal-Organic Frameworks ; chemical synthesis ; chemistry ; Models, Theoretical ; Nanoparticles ; chemistry ; Strontium ; analysis ; Surface Properties ; Water Pollutants, Radioactive ; analysis ; Water Purification ; methods

To analyze types of urinary calculi and patients' clinical characteristics, and to explore the strategies for prevention and treatment of urinary calculi.
 Methods: A total of 1 849 patients with urinary calculi were treated in the Department of Urology, the Third Xiangya Hospital of Central South University. The components were analyzed by infrared spectroscopy. The relationship between stone composition and clinical parameters was analyzed according to the clinical characteristics of the patients.
 Results: The proportion of calcium oxalate stone or uric acid stone in male (84.1% or 7.7%) was higher than that in female (78.4% or 4.2%). The older patients were more likely to be diagnosed as uric acid stone. The proportions of uric acid stone in patients <18 years old, 18-<41 years old, 41-<66 years old, and ≥66 years old were 0.0%, 1.6%, 6.6%, and 12.4%, respectively. There was no significant difference in the proportion of stones in patients with different BMI. There were no significant difference in the stone composition between the patients with or without urinary tract infection, hypertension or diabetes. The proportion of uric acid stones in patients with acidic urine was higher than the other types. The proportion of uric acid stones in patients with elevated creatinine (12.1%) was higher than that in the patients with normal creatinine (4.5%).
 Conclusion: Elderly patients, or patients with high uric acid and renal insufficiency are more prone to uric acid stones. Regulation of urinary pH may be an important strategy for preventing and treating urinary calculi in Hunan Province.
Adolescent ; Adult ; Age Factors ; Aged ; Body Mass Index ; Calcium Oxalate ; analysis ; Creatinine ; urine ; Female ; Humans ; Hydrogen-Ion Concentration ; Kidney Calculi ; chemistry ; therapy ; Male ; Middle Aged ; Sex Factors ; Spectrophotometry, Infrared ; Uric Acid ; analysis ; Urinary Calculi ; chemistry ; therapy ; urine

OBJECTIVES: Aluminum phosphide (ALP), also known in Iran as rice tablets, is one of the most effective rodenticides used to protect stored grain. However, ALP poisoning regularly causes mortality in humans. The aim of this study was to evaluate the characteristics and predictive factors of mortality from ALP poisoning.METHODS: This study evaluated all patients with ALP poisoning referred to Imam Khomeini Hospital in Kermanshah Province, Iran from 2014 to 2015. For each patient, the following information was recorded: age, sex, the number of tablets consumed, the number of suicide attempts, the time elapsed from consumption to treatment, blood pressure, blood pH, HCO3 levels, and PCO2. Differences between the survivors and non-survivors of ALP poisoning were analyzed using univariate logistic regression and multivariate analysis.RESULTS: In this study, 48 patients were male and 29 patients were female (total: 77 patients). The average age of the survivors and non-survivors was 28.7 and 31.3 years, respectively. All cases (100%) of ALP poisoning were intentional, with the goal of committing suicide. The main predictive variables of mortality from ALP poisoning were blood pressure, blood pH, and time elapsed from consumption to treatment.CONCLUSIONS: The likelihood of mortality in patients with ALP poisoning can be predicted using blood pressure, blood pH, and time elapsed from consumption to treatment. These findings may help healthcare providers take more effective measures to treat patients with ALP poisoning.
Aluminum ; Blood Pressure ; Clergy ; Female ; Health Personnel ; Humans ; Hydrogen-Ion Concentration ; Iran ; Logistic Models ; Male ; Mortality ; Multivariate Analysis ; Poisoning ; Rodenticides ; Suicide ; Survivors ; Tablets