Proteomics is one of the most important functional genomics research in the post-genomic era, which is closely related to medical biology, chemistry, physics, information science and modern technology. Through review research progress of some important proteomics, a proteomics special issue is published so as to find problems, explore the possible applications and outlook the development prospects of proteomics. The special issue consists of reviews and original papers, mainly involving in the following aspects, i) proteomics about different species such as humans, mammals, prokaryotes and actinobacterial; ii) proteomics methodology and techniques including tandem mass spectrometry analysis, film (urimem) preservation of urine protein, quantitative proteomic analysis and meta analysis; iii) function and application of proteome such as spider (Latrodectus tredecimguttatus) toxins proteome, protein phosphorylation proteome, oocytes and early embryos proteomes, liver fibrosis proteome, drug-resistant mycobacterium tuberculosis proteome, etc.
Animals ; Humans ; Proteome ; Proteomics ; Tandem Mass Spectrometry

In this study,liquiritigenin sulfonation was characterized using recombinant human sulfotransferases( SULTs). The chemical structure of liquiritigenin sulfate was determined by ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry( UPLC-Q-TOF-MS/MS). Then model fitting and parameter estimation were performed using the Graphpad Prism V5 software. Various SULT enzymes( SULT1 A1,1 A2,1 A3,1 B1,1 C2,1 C4,1 E1 and 2 A1) were able to catalyze the formation of liquiritigenin-7-O-sulfate. Sulfonation of liquiritigenin-7-hydroxy( 7-OH) by these eight SULT enzymes consistently displayed the classical Michaelis-Menten profile. According to the intrinsic clearance( CLint) value,the sulfonation rates of liquiritigenin-7-OH by expressed SULT enzymes followed the following rank order: SULT1 C4 > SULT1 A3 > SULT1 E1 > SULT1 A1 > SULT1 A2 > SULT1 B1 >SULT1 C2>SULT2 A1. Further,liquiritigenin-7-O-sulfonation was significantly correlated with the SULT1 A3 protein levels( P<0. 05).Then,human embryonic kidney( HEK) 293 cells over expressing SULT1 A3( named as HEK-SULT1 A3 cells) were conducted. As a result,liquiritigenin-7-O-sulfate( L-7-S) was rapidly generated upon incubation of the cells with liquiritigenin. Consistent with SULT1 A3,sulfonation of liquiritigenin-7-OH in HEK-SULT1 A3 cells also followed the Michaelis-Menten kinetics. The derived Vmaxvalues was( 0. 315±0. 009) μmol·min-1·g-1,Kmwas( 7. 04±0. 680) μmol·L^-1,and CLintwas( 0. 045±0. 005) L·min^-1·g^-1. Moreover,the sulfonation characters of liquiritigenin( 7-OH) in SULT1 A3 were strongly correlated with that in HEK-SULT1 A3 cells( P<0. 001).The results indicated that HEK-SULT1 A3 cells have shown the catalytic function of SULT1 A3 enzymes. In conclusion,liquiritigenin was subjected to efficient sulfonation,and SULT1 A3 enzyme plays an important role in the sulfonation of liquiritigenin-7-OH. Significant sulfonation should be the main reason for the low bioavailability of liquiritigenin. In addition,HEK-SULT1 A3 cells were conducted and successfully used to evaluate liquiritigenin sulfonation,which will provide an appropriate tool to accurately depict the sulfonation disposition of liquiritigenin in vivo.
Arylsulfotransferase ; Flavanones/metabolism* ; Humans ; Tandem Mass Spectrometry

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) combines the advantages of high separation ability of chromatography and high selectivity, specificity and sensitivity of mass spectrometry, making it one of the most vibrant new technologies in the field of clinical testing. However, the analytical performance is often limited by the characteristics of the sample to be measured. Due to the limited anti-contamination capability of the mass spectrometer, biological samples need to be properly pre-processed to effectively improve the detection performance and achieve accurate detection. The main function of pre-treatment is to selectively separate the target analyte from the biological matrix to reduce interference from other matrix components. At the same time, the target analytes can be concentrated and enriched to improve the analytical sensitivity. At present, there are many kinds of clinical sample pre-treatment methods, and several methods are time-consuming and cumbersome, which brings difficulties to laboratory personnel in method selection, development and standardized operation. Therefore, the purpose of this consensus is to provide guidance for the establishment of laboratory methods and facilitate the standardized development of clinical mass spectrometry measurement.
Humans ; Chromatography, Liquid ; Consensus ; Tandem Mass Spectrometry

OBJECTIVEWe established a method of UPLC-MS/MS that was to detect fifteen precursors of perfluoroalkyl sulfonates (PFSA) and perfluoroalkyl carboxylates (PFCA) in serum.

METHODSBriefly, TBAS solution was added to sera, then the mixed solution was extracted with aliquots of MTBE. The MTBE aliquots were combined, evaporated to dryness under nitrogen, and reconsituted in 0.25 ml of methanol and water (1:1). Then the reconstituted solution through 0.2 µm nylon syringe filter was collected. Chromatographic separation was performed using a Waters ACQUITY (TM) BEH ¹⁸C column (50 mm × 2.1 mm × 1.7 mm). Analyte quantitation was performed in the negative electrospray ionization mode and multiple reaction monitoring (MRM).

RESULTSThree target substances, 6: 6PFPi, 6: 8PFPi, 8: 8PFPi, were externally confirmed by standard addition. Rates of recovery for these three chemicals were from 41.01% to 112.13% in two standard levels. And the relative standard deviations (RSD) were lower than 11.63% and higher than 1.80%. The other twelve substances were quantified with internal standard. Moreover in two standard levels, rate of recovery for these chemicals ranged from 70.25% to 127.51%. And RSD were more than 1.23% and less than 15.45%. And the corresponding limit of detection (LOD) and limit of quantitation (LOQ) for all target substances were 0.1-5.0 pg/ml and 0.2-10.0 pg/ml. Then we detected these target substances in ten different human serum samples. The levels of few substances were higher than LOD. And the ranges of FOSA-M, N-EtFOSA-M, N-MeFOSAA, N-EtFOSAA were respectively < LOD-0.94 pg/ml, < LOD-10.08 pg/ml, < LOD-6.74 pg/ml, < LOD-1.04 pg/ml.

CONCLUSIONThe method, with high sensitivity and accuracy, could meet the actual testing requirements.

A rapid, sensitive and convenient LC-MS/MS method was developed for the determination of γ-aminobutyric acid (GABA) in human plasma. d2-γ-Aminobutyric acid (d2-GABA) was synthesized as internal standard (IS). After extraction from human plasma by protein precipitation with acetonitrile, all analytes were separated on a Luna HILIC column (100 mm x 3.0 mm, 3 μm) using an isocratic mobile phase of water: acetonitrile: formic acid (20 : 80 : 0.12) with a flow rate of 0.5 mL x min(-1). Acquisition of mass spectrometric data was performed in multiple reaction monitoring mode (MRM) in positive electrospray ionization using the transitions of m/z 104 --> 69 for GABA and m/z 106 --> 71 for d2-GABA. The method was linear in the concentration range of 5.00 to 1 000 ng x mL(-1). The intra- and inter-day precisions were within 9.9%, and accuracy ranged from 99.1% to 104%, within the acceptable limit across all concentrations. The method was successfully applied to a pharmacokinetic study of GABA tablets in healthy Chinese volunteers.
Chromatography, Liquid ; Humans ; Tandem Mass Spectrometry ; gamma-Aminobutyric Acid ; blood

Objective: To establish an ultrahigh performance liquid chromatography tandem mass spectrometry method for the determination of creatinine (Cre) and 2-thiothiazolidine-4-carboxylic acid (TTCA) in urine. Methods: In October 2020, the end-of-shift urine samples of the monitored subjects were taken, and the filtrate was prepared by centrifugation. After separated by ultra high performance liquid chromatography C18 column, acetonitrile and 0.2% acetic acid aqueous solution were used as mobile phases for gradient elution, the three quadrupole tandem mass spectrometry adopted an electrospray ion source (ESI) , the ion source temperature was 500 ℃ , and the air curtain gas flow rate was 31.4 L/min, qualitative and quantitative analysis of Cre and TTCA were carried out under the multiple reaction monitoring mode. Results: The linear range of Cre was 1.0-1 000.0 μg/L, the linear equation was y=947.3x-1605.6, and the correlation coefficient was 0.9994. The detection limit and the limit of quantitation were 0.3, 1.0 μg/L. When the addition concentrations were 50.0, 150.0 and 450.0 μg/L, the recovery rates were 92.8%-94.6% , the intra assay precisions were 3.6%-5.7% , and the inter assay precisions were 3.4%-5.4%. The linear range of TTCA was 0.1-200.0 μg/L, the linear equation was y=1164.7x-2243.9, and the correlation coefficient was 0.9991. The detection limit and the limit of quantitation were 0.03, 0.1 μg/L. When the addition concentrations were 10.0, 40.0 and 160.0 μg/L, the recovery rates were 90.8%-93.6%, the intra assay precisions were 4.6%-7.4%, and the inter assay precisions were 4.4%-6.9%. Conclusion: The sample pretreatment process of the ultra high performance liquid chromatography tandem mass spectrometry method for the determination of Cre and TTCA in urine is simple, and the continuous determination of Cre and TTCA in urine can be realized only by switching mass spectrometry parameters under the same chromatographic conditions, which is accurate and efficient, and each performance index of the method meets the determination requirements.
Chromatography, High Pressure Liquid ; Creatinine ; Humans ; Tandem Mass Spectrometry ; Thiazolidines

The present study investigated the effect of immersion in the excipient lime water on the toxic component lectin protein and explained the scientific connotation of lime water detoxication during the processing of Pinelliae Rhizoma Praeparatum. Western blot was used to investigate the effects of immersion in lime water with different pH(pH 10, 11, and 12.4), saturated sodium hydroxide, and sodium bicarbonate solution on the content of lectin protein. The protein compositions of the supernatant and the precipitate after immersing lectin protein in lime water of different pH were determined by the SDS-PAGE method combined with the silver staining technique. The MALDI-TOF-MS/MS technique was used to detect the molecular weight distribution of peptide fragments in the supernatant and precipitate after immersing lectin protein in lime water of different pH, and circular dichroism spectroscopy was used to detect the ratio changes in the secondary structure of lectin protein during the immersion. The results showed that immersion in lime water at pH>12 and saturated sodium hydroxide solution could significantly reduce the content of lectin protein, while immersion in lime water at pH<12 and sodium bicarbonate solution had no significant effect on lectin protein content. The corresponding lectin protein bands and molecular ion peaks were not detected at the 12 kDa position in the supernatant and precipitate after immersing the lectin protein in lime water at pH>12, which was attributed to the fact that lime water immersion at pH>12 could significantly change the ratio of the secondary structure of lectin protein, resulting in irreversible denaturation, while lime water immersion at pH<12 did not change the ratio of the secondary structure of lectin protein. Therefore, pH>12 was the key condition for the detoxication of lime water during the processing of Pinelliae Rhizoma Praeparatum. Lime water immersion at pH>12 could cause irreversible denaturation of lectin protein, resulting in a significant decrease in the inflammatory toxicity of Pinelliae Rhizoma Praeparatum, which played a key role in detoxification.
Lectins ; Pinellia ; Sodium Bicarbonate ; Sodium Hydroxide ; Tandem Mass Spectrometry ; Water

Qualitative and quantitative analysis of 2-(2-phenylethyl) chromones in sodium chloride(NaCl)-treated suspension cells of Aquilaria sinensis was conducted by UPLC-Q-Exactive-MS and UPLC-QQQ-MS/MS. Both analyses were performed on a Waters T3 column(2.1 mm×50 mm, 1.8 μm) with 0.1% formic acid aqueous solution(A)-acetonitrile(B) as mobile phases at gradient elution. MS data were collected by electrospray ionization in positive ion mode. Forty-seven phenylethylchromones was identified from NaCl-treated suspension cell samples of A. sinensis using UPLC-Q-Exactive-MS, including 22 flindersia-type 2-(2-phenylethyl) chromones and their glycosides, 10 5,6,7,8-tetrahydro-2-(2-phenylethyl) chromones and 15 mono-epoxy or diepoxy-5,6,7,8-tetrahydro-2-(2-phenylethyl) chromones. Additionally, 25 phenylethylchromones were quantitated by UPLC-QQQ-MS/MS. Overall, the rapid and efficient qualitative and quantitative analysis of phenylethylchromones in NaCl-treated suspension cells of A. sinensis by two LC-MS techniques, provides an important reference for the yield of phenylethylchromones in Aquilariae Lignum Resinatum using in vitro culture and other biotechnologies.
Chromones ; Sodium Chloride ; Chromatography, Liquid ; Flavonoids ; Tandem Mass Spectrometry ; Thymelaeaceae

Ganoderma lingzhi is widely recognized as a medicinal basidiomycetes. Triterpene acids (TAs) are the key bioactive medicinal components of G. lingzhi. Our previous studies have shown that phospholipid acid (PA) produced by phospholipase D (PLD) plays a regulatory role in TA synthesis. In order to further elucidate the molecular mechanism how PA regulates TA synthesis in G. lingzhi, PA beads enrichment combined with LC-MS/MS technology was used to identify PA interacting proteins in G. lingzhi. A total of 19 PA interacting proteins were identified, including cytochrome P450 monooxygenase (GL22084), specific protein kinase MAPK (GL23765), catalase and cell surface hydrophobicity-associated protein. GST tagged GL22084 and GL23765 proteins were obtained through gene cloning, heterologous expression, and purification. The interactions between GL22084/GL23765 and PA were verified by GST pull down assay. The identification of PA interacting proteins provides a basis for further understanding the molecular mechanism how PLD-mediated PA signaling molecules regulates the TA synthesis in G. lingzhi. Moreover, the PA interacting proteins identified in this study can also provide clues for the research of PLD/PA signaling pathway in other species.
Chromatography, Liquid ; Ganoderma ; Phosphatidic Acids ; Tandem Mass Spectrometry

Fusarium is the major pathogen of root rot of Pseudostellaria heterophylla. This study aims to explain the possible distribution of Fusarium species and the contamination of its toxin-chemotypes in tuberous root of P. heterophylla. A total of 89 strains of fungi were isolated from the tuberous root of P. heterophylla. Among them, 29 strains were identified as Fusarium by ITS2 sequence, accounting for 32.5%. They were identified as five species of F. avenaceum, F. tricinctum, F. fujikuroi, F. oxysporum, and F. graminearum based on β-Tubulin and EF-1α genes. LC-MS/MS detected 18, 1, and 5 strains able to produce ZEN, DON, and T2, which accounted for 62.1%, 3.4%, and 17.2%, respectively. Strain JK3-3 can produce ZEN, DON, and T2, while strains BH1-4-1, BH6-5, and BH16-2 can produce ZEN and T2. PCR detected six key synthase genes of Tri1, Tri7, Tri8, Tri13, PKS14, and PKS13 in strain JK3-3, which synthesized three toxins of ZEN, DON, and T2. Four key synthase genes of Tri8, Tri13, PKS14, and PKS13 were detected in strains BH1-4-1, BH6-5, and BH16-2, which were responsible for the synthesis of ZEN and T2. The results showed that the key genes of toxin biosynthesis were highly correlated with the toxins produced by Fusarium, and the biosynthesis of toxin was strictly controlled by the genetic information of the strain. This study provides a data basis for the targeted prevention and control of exo-genous mycotoxins in P. heterophylla and a possibility for the development of PCR for rapid detection of toxin contamination.
Caryophyllaceae ; Chromatography, Liquid ; Fusarium/genetics* ; Mycotoxins ; Tandem Mass Spectrometry