Publications by authors named "Takashi Nirasawa"

16 Publications

  • Page 1 of 1

Breast cancer proliferation and deterioration-associated metabolic heterogeneity changes induced by exposure of bisphenol S, a widespread replacement of bisphenol A.

J Hazard Mater 2021 Feb 19;414:125391. Epub 2021 Feb 19.

State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, Hong Kong SAR, China. Electronic address:

Exposure to bisphenol A (BPA) is considered to be associated with the increased incidence of breast cancer. As a widespread replacement of BPA, the effect of bisphenol S (BPS) on breast tumor programming has not been studied. We reported that BPS exposure significantly promoted proliferation and deterioration of breast tumor by nonmonotonic dose response. The mechanisms were investigated by molecular biology and mass spectrometry-based lipidomics, proteomics and imaging. BPS exposure induced the spatially intratumor heterogeneity of morphology-driven lipids and proteins. The more significant proliferation resulted from BPS-10 (10 μg/kg body weight /day) exposure was evidenced by the variations of spatial distribution of lipids related to ceramide-sphingomyelin signaling pathway, proteins related to chromosomal stability and cell proliferation in central necrotic regions of breast tumor. In contrast, the BPS-100 exposure obviously accelerated deterioration of breast tumor by the variations of spatial distribution of proteins that were associated with the stability of nucleic acid structure in peripheral neoplastic regions. Accordingly, dysregulation of metabolism and protein function as well as DNA methylation and hypoxic tumor microenvironment could be applied to predict the possibility of tumorigenesis, proliferation and metastasis that might be caused by other bisphenol analogs.
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http://dx.doi.org/10.1016/j.jhazmat.2021.125391DOI Listing
February 2021

Localization of Flavan-3-ol Species in Peanut Testa by Mass Spectrometry Imaging.

Molecules 2020 May 20;25(10). Epub 2020 May 20.

Application Department Daltonics Division, Bruker Japan K.K., Yokohama 221-0022, Japan.

Flavan-3-ols, procyanidins and their monomers are major flavonoids present in peanuts that show a wide range of biological properties and health benefits, based on their potent antioxidant activity. Procyanidin oligomers, especially A-type, are reportedly abundant in peanut skin; however, their localization in the raw peanut testa remains poorly understood. Therefore, we performed matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) to investigate the localization of flavan-3-ols in peanut testa. 1,5-Diaminonaphthalene was coated onto the peanut section by matrix vapor deposition/recrystallization, and MALDI-MSI measurements were performed in the negative-ion mode. Peaks matching the / values of flavan-3-ol [M - H] ions were observed in the mass spectrum extracted from the outer epidermis of the peanut testa, using the region of interest function. Catechin and/or epicatechin, five A-type, and one B-type procyanidins were assigned by the fragment ions generated by retro-Diels-Alder, heterocyclic ring fission, and quinone methide reactions detected in MALDI-tandem MS spectra. These flavan-3-ols were localized in the outer epidermis of the peanut testa. This information will contribute to improving the extraction and purification efficiencies of flavan-3-ols from peanut testa. As flavan-3-ols display anti-microbial activity, it is speculated that flavan-3-ols present in the outer epidermis of peanut testa act to prevent pathogen infection.
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http://dx.doi.org/10.3390/molecules25102373DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7287834PMC
May 2020

Brain-transportable dipeptides across the blood-brain barrier in mice.

Sci Rep 2019 04 8;9(1):5769. Epub 2019 Apr 8.

Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School of Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan.

Apart from nutrients required for the brain, there has been no report that naturally occurring peptides can cross the blood-brain barrier (BBB). The aim of this study was to identify the BBB-transportable peptides using in situ mouse perfusion experiments. Based on the structural features of Gly-N-methylated Gly (Gly-Sar), a reported BBB-transportable compound, 18 dipeptides were synthesized, and were perfused in the mouse brain for two minutes. Among the synthesized dipeptides, Gly-Sar, Gly-Pro, and Tyr-Pro were transported across the BBB with K values of 7.60 ± 1.29, 3.49 ± 0.66, and 3.53 ± 0.74 µL/g·min, respectively, and accumulated in the mouse brain parenchyma. Additionally, using MALDI-MS/MS imaging analysis of Tyr-Pro-perfused brain, we provide evidence for Tyr-Pro accumulation in the hippocampus, hypothalamus, striatum, cerebral cortex, and cerebellum of mouse brain.
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http://dx.doi.org/10.1038/s41598-019-42099-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6453885PMC
April 2019

Visualization of Amyloid β Deposits in the Human Brain with Matrix-assisted Laser Desorption/Ionization Imaging Mass Spectrometry.

J Vis Exp 2019 03 7(145). Epub 2019 Mar 7.

Graduate School of Brain Science, Doshisha University.

The neuropathology of Alzheimer's disease (AD) is characterized by the accumulation and aggregation of amyloid β (Aβ) peptides into extracellular plaques of the brain. The Aβ peptides, composed of 40 amino acids, are generated from amyloid precursor proteins (APP) by β- and γ-secretases. Aβ is deposited not only in cerebral parenchyma but also in leptomeningeal and cerebral vessel walls, known as cerebral amyloid angiopathy (CAA). While a variety of Aβ peptides were identified, the detailed production and distribution of individual Aβ peptides in pathological tissues of AD and CAA have not been fully addressed. Here, we develop a protocol of matrix-assisted laser desorption/ionization-based imaging mass spectrometry (MALDI-IMS) on human autopsy brain tissues to obtain comprehensive protein mapping. For this purpose, human cortical specimens were obtained from the Brain Bank at the Tokyo Metropolitan Institute of Gerontology. Frozen cryosections are cut and transferred to indium-tin-oxide (ITO)-coated glass slides. Spectra are acquired using the MALDI system with a spatial resolution up to 20 µm. Sinapinic acid (SA) is uniformly deposited on the slide using either an automatic or a manual sprayer. With the current technical advantages of MALDI-IMS, a typical data set of various Aβ species within the same sections of human autopsied brains can be obtained without specific probes. Furthermore, high-resolution (20 µm) imaging of an AD brain and severe CAA sample clearly shows that Aβ1-36 to Aβ1-41 were deposited into leptomeningeal vessels, while Aβ1-42 and Aβ1-43 were deposited in cerebral parenchyma as senile plaque (SP). It is feasible to adopt MALDI-IMS as a standard approach in combination with clinical, genetic, and pathological observations in understanding the pathology of AD, CAA, and other neurological diseases based on the current strategy.
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http://dx.doi.org/10.3791/57645DOI Listing
March 2019

Alternative pathway of HS and polysulfides production from sulfurated catalytic-cysteine of reaction intermediates of 3-mercaptopyruvate sulfurtransferase.

Biochem Biophys Res Commun 2018 02 10;496(2):648-653. Epub 2018 Jan 10.

Department of Analytical Biochemistry, Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose-shi, Tokyo, 204-8588, Japan. Electronic address:

It has been known that hydrogen sulfide and/or polysulfides are produced from a (poly)sulfurated sulfur-acceptor substrate of 3-mercaptopyruvate sulfurtransferase (MST) via thioredoxin (Trx) reduction in vitro. In this study, we used thiosulfate as the donor substrate and the catalytic reaction was terminated on the formation of a persulfide or polysulfides. We can present alternative pathway of production of hydrogen sulfide and/or polysulfides from (poly)sulfurated catalytic-site cysteine of reaction intermediates of MST via Trx reduction. Matrix-assisted laser desorption ionization tandem time-of-flight mass spectrometric analysis revealed that after prolonged incubation of MST with thiosulfate, a trisulfide adduct becomes predominant at the sulfurated catalytic-site cysteine. When these adducts were reduced by Trx with reducing system (MST:Escherichia coli Trx:E. coli Trx reductase:NADPH = 1:5:0.02:12.5 molar ratio), liquid chromatography with tandem mass spectrometric analysis for monobromobimane-derivatized HS revealed that HS first appeared, and then HS and HS did later. The results were confirmed by high-performance liquid chromatography-fluorescence analysis.
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http://dx.doi.org/10.1016/j.bbrc.2018.01.056DOI Listing
February 2018

Distinct deposition of amyloid-β species in brains with Alzheimer's disease pathology visualized with MALDI imaging mass spectrometry.

Acta Neuropathol Commun 2017 10 16;5(1):73. Epub 2017 Oct 16.

Genomics, Proteomics and Biomedical Functions, Department of Life and Medical Systems, Faculty of Life and Medical Sciences, Doshisha University, Kyoto, Japan.

Amyloid β (Aβ) deposition in the brain is an early and invariable feature of Alzheimer's disease (AD). The Aβ peptides are composed of about 40 amino acids and are generated from amyloid precursor proteins (APP), by β- and γ-secretases. The distribution of individual Aβ peptides in the brains of aged people, and those suffering from AD and cerebral amyloid angiopathy (CAA), is not fully characterized. We employed the matrix-assisted laser desorption/ionization-imaging mass spectrometry (MALDI-IMS) to illustrate the spatial distribution of a broad range of Aβ species in human autopsied brains. With technical advancements such as formic acid pretreatment of frozen autopsied brain samples, we have: i) demonstrated that Aβ1-42 and Aβ1-43 were selectively deposited in senile plaques while full-length Aβ peptides such as Aβ1-36, 1-37, 1-38, 1-39, 1-40, and Aβ1-41 were deposited in leptomeningeal blood vessels. ii) Visualized distinct depositions of N-terminal truncated Aβ40 and Aβ42, including pyroglutamate modified at Glu-3 (N3pE), only with IMS for the first time. iii) Demonstrated that one single amino acid alteration at the C-terminus between Aβ1-42 and Aβ1-41 results in profound changes in their distribution pattern. In vitro, this can be attributed to the difference in the self-aggregation ability amongst Aβ1-40, Aβ1-41, and Aβ1-42. These observations were further confirmed with immunohistochemistry (IHC), using the newly developed anti-Aβ1-41 antibody. Here, distinct depositions of truncated and/or modified C- and N-terminal fragments of Aβs in AD and CAA brains with MALDI-IMS were visualized in a spacio-temporal specific manner. Specifically, Aβ1-41 was detected both with MALDI-IMS and IHC suggesting that a single amino acid alteration at the C-terminus of Aβ results in drastic distribution changes. These results suggest that MALDI-IMS could be used as a standard approach in combination with clinical, genetic, and pathological observations in understanding the pathology of AD and CAA.
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http://dx.doi.org/10.1186/s40478-017-0477-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5641992PMC
October 2017

Chronological Profiling of Plasma Native Peptides after Hepatectomy in Pigs: Toward the Discovery of Human Biomarkers for Liver Regeneration.

PLoS One 2017 6;12(1):e0167647. Epub 2017 Jan 6.

Department of Genomic Medical Sciences, Kyoto Prefectural University of Medicine, Graduate School of Medical Science, Kyoto, Japan.

Liver regeneration after partial hepatectomy (PHx) is a time-dependent process, which is tightly regulated by multiple signaling cascades. Failure of this complex process leads to posthepatectomy liver failure (PHLF), which is associated with a high rate of mortality. Thus, it is extremely important to establish a useful biomarker of liver regeneration to help prevent PHLF. Here, we hypothesized that alterations in the plasma peptide profile may predict liver regeneration following PHx and hence we set up a diagnostic platform for monitoring posthepatectomy outcome. We chronologically analyzed plasma peptidomic profiles of 5 partially hepatectomized microminipigs using the ClinProtTM system, which consists of magnetic beads and MALDI-TOF/TOF MS. We identified endogenous circulating peptides specific to each phase of the postoperative course after PHx in pigs. Notably, peptide fragments of histones were detected immediately after PHx; the presence of these fragments may trigger liver regeneration in the very acute phase after PHx. An N-terminal fragment of hemoglobin subunit α (3627 m/z) was detected as an acute-phase-specific peptide. In the recovery phase, the short N-terminal fragments of albumin (3028, 3042 m/z) were decreased, whereas the long N-terminal fragment of the protein (8926 m/z) was increased. To further validate and extract phase-specific biomarkers using plasma peptidome after PHx, plasma specimens of 4 patients who underwent PHx were analyzed using the same method as we applied to pigs. It revealed that there was also phase-specificity in peptide profiles, one of which was represented by a fragment of complement C4b (2378 m/z). The strategy described herein is highly efficient for the identification and characterization of peptide biomarkers of liver regeneration in a swine PHx model. This strategy is feasible for application to human biomarker studies and will yield clues for understanding liver regeneration in human clinical trials.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0167647PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5218562PMC
August 2017

Dimerization of HIV-1 protease occurs through two steps relating to the mechanism of protease dimerization inhibition by darunavir.

Proc Natl Acad Sci U S A 2014 Aug 4;111(33):12234-9. Epub 2014 Aug 4.

Departments of Hematology, Rheumatology, and Infectious Disease, Kumamoto University Graduate School of Medicine, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan;Experimental Retrovirology Section, HIV and AIDS Malignancy Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892;

Dimerization of HIV-1 protease (PR) subunits is an essential process for PR's acquisition of proteolytic activity, which plays a critical role in the maturation of HIV-1. Recombinant wild-type PR (PR(WT)) proved to dimerize, as examined with electrospray ionization mass spectrometry; however, two active site interface PR mutants (PR(T26A) and PR(R87K)) remained monomeric. On the other hand, two termini interface PR mutants (PR(1-C95A) and PR(97/99)) took both monomeric and dimeric forms. Differential scanning fluorimetry indicated that PR(1-C95A) and PR(97/99) dimers were substantially less stable than PR(WT) dimers. These data indicate that intermolecular interactions of two monomers occur first at the active site interface, generating unstable or transient dimers, and interactions at the termini interface subsequently occur, generating stable dimers. Darunavir (DRV), an HIV-1 protease inhibitor, inhibits not only proteolytic activity but also PR dimerization. DRV bound to protease monomers in a one-to-one molar ratio, inhibiting the first step of PR dimerization, whereas conventional protease inhibitors (such as saquinavir) that inhibit enzymatic activity but not dimerization failed to bind to monomers. DRV also bound to mutant PRs containing the transframe region-added PR (TFR-PR(D25N) and TFR-PR(D25N-7AA)), whereas saquinavir did not bind to TFR-PR(D25N) or TFR-PR(D25N-7AA). Notably, DRV failed to bind to mutant PR containing four amino acid substitutions (V32I, L33F, I54M, and I84V) that confer resistance to DRV on HIV-1. To our knowledge, the present report represents the first demonstration of the two-step PR dimerization dynamics and the mechanism of dimerization inhibition by DRV, which should help design further, more potent novel PIs.
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http://dx.doi.org/10.1073/pnas.1400027111DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4142999PMC
August 2014

Quantitative mass barcode-like image of nicotine in single longitudinally sliced hair sections from long-term smokers by matrix-assisted laser desorption time-of-flight mass spectrometry imaging.

J Anal Toxicol 2014 Jul-Aug;38(6):349-53. Epub 2014 May 6.

Department of Clinical and Laboratory Medicine, Osaka Medical College, 2-7 Daigaku-cho, Takatsuki, Osaka 569-8686, Japan.

The matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometric technique (IMS) offered a new breakthrough perspective in the analysis of drug abuse in forensic science; however, it only produced barcode-like images, semi-quantitative analysis. In order to develop intermittent monitoring by this IMS for forensic and medical sciences, it is important to quantitatively measure the contents of longitudinally sliced hair sections. We developed quantitative imaging mass spectrometry (QIMS) of nicotine (NC) in longitudinally sliced hairs by MALDI-IMS with the selected reaction monitoring mode using a labeled NC ((13)C3-NC) standard for the serially chronological monitoring and traceability of NC intake in heavy smokers. The calibration curve of NC/(13)C3-NC was virtually a linear equation at ranges from 1 to 50 ng/mL, the slope was 0.020, and the intercept was almost 0.023 and the R(2) was 0.9965. The limit of quantitation of NC was calculated as 1.6 ng/mg hair (an average weight of the hair would be assumed 0.06 mg/cm) by QIMS. Moreover, NC concentrations in two separate heavy smokers (n = 3) were 8.5 ± 1.2 and 34.5 ± 2.8 ng/mg hair, respectively, and covariations were ∼10% using a single hair. Quantitative mass barcode-like image of sliced section of hair allowed for the quantitative assessment of NC concentrations in long-term smokers similar to drugs and medicines during drug histories.
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http://dx.doi.org/10.1093/jat/bku032DOI Listing
June 2015

Topologies of amyloidogenic proteins in Congo red-positive sliced sections of formalin-fixed paraffin embedded tissues by MALDI-MS imaging coupled with on-tissue tryptic digestion.

Clin Biochem 2013 Oct 31;46(15):1595-600. Epub 2013 May 31.

Department of Clinical and Laboratory Medicine, Osaka Medical College, 2-7 Daigaku-cho, Takatsuki-city 569-8668, Osaka, Japan. Electronic address:

Objectives: Matrix-assisted laser desorption time-of flight ionization (MALDI)-imaging MS (IMS) with MSMS analysis using on-tissue tryptic digests is a powerful tool for identification of disease-related proteins in formalin-fixed paraffin-embedded (FFPE) tissue sections. We applied this novel IMS technique, not only to identify tryptic peptides of deposited amyloidogenic proteins but also to clarify topologies of these proteins in amyloidosis tissue sections.

Methods: Sequence determinations of tryptic peptides derived from amyloidogenic proteins were performed using MALDI-MSMS analysis directly from Congo red positive regions in tissue sections with/without procedure for retrieval of epitopes before on-tissue digestion.

Results: Tryptic peptides, m/z=1073.5 and 1924.3 were identified with the sequences, from 48th to 56th and 1st to 19th positions of Ig lambda V-III region, respectively. Other peptides, m/z=1365.5 and 1523.5 were with the sequences, from 22nd to 34th and 36th to 48th positions of TTR, respectively. Heat-map images of all four tryptic peptides were overlapped with Congo red positive regions. Immunohistochemistry of FFPE tissue sections was confirmed to only react with anti-λ chain antibody in a case of AL-type amyloidosis or anti-TTR antibody in two cases of TTR-type amyloidosis.

Conclusion: IMS with MSMS analysis using on-tissue tryptic digestion enables us not only to identify amyloidogenic molecule in a sliced tissue section but also to play a complementary role with the conventional pathological examination.
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http://dx.doi.org/10.1016/j.clinbiochem.2013.05.063DOI Listing
October 2013

Cerebrospinal fluid proteomic patterns discriminate Parkinson's disease and multiple system atrophy.

Mov Disord 2012 Jun 1;27(7):851-7. Epub 2012 Jun 1.

Department of Neurology, Kyoto Prefectural University of Medicine, Kamigyo-ku, Kyoto, Japan.

The differential diagnosis of Parkinson's disease and multiple system atrophy can be challenging, especially in the early stages of the diseases. We developed a proteomic profiling strategy for parkinsonian diseases using mass spectrometry analysis for magnetic-bead-based enrichment of cerebrospinal fluid peptides/proteins and subsequent multivariate statistical analysis. Cerebrospinal fluid was obtained from 37 patients diagnosed with Parkinson's disease, 32 patients diagnosed with multiple system atrophy, and 26 patients diagnosed with other neurological diseases as controls. The samples were from the first cohort and the second cohort. Cerebrospinal fluid peptides/proteins were purified with C8 magnetic beads, and spectra were obtained by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Principal component analysis and support vector machine methods are used to reduce dimension of the data and select features to classify diseases. Cerebrospinal fluid proteomic profiles of Parkinson's disease, multiple system atrophy, and control were differentiated from each other by principal component analysis. By building a support vector machine classifier, 3 groups were classified effectively with good cross-validation accuracy. The model accuracy was well preserved for both cases, training by the first cohort and validated by the second cohort and vice versa. Receiver operating characteristics proved that the peak of m/z 6250 was the most important to differentiate multiple system atrophy from Parkinson's disease, especially in the early stages of the disease. A proteomic pattern classification method can increase the accuracy of clinical diagnosis of Parkinson's disease and multiple system atrophy, especially in the early stages.
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http://dx.doi.org/10.1002/mds.24994DOI Listing
June 2012

Proteomic pattern analysis discriminates among multiple sclerosis-related disorders.

Ann Neurol 2012 May;71(5):614-23

Department of Neurology, Graduate School of Medicine, Kyoto University, Japan.

Objective: To use a new, unbiased biomarker discovery strategy to obtain and assess proteomic data from cerebrospinal fluid (CSF) of patients with multiple sclerosis (MS)-related disorders.

Methods: CSF protein profiles were analyzed from 107 patients with either MS-related disorders (including relapsing remitting MS [RRMS], primary progressive MS [PPMS], anti-aquaporin4 antibody seropositive-neuromyelitis optica spectrum disorder [SP-NMOSD], and seronegative-NMOSD with long cord lesions on spinal magnetic resonance imaging [SN-NMOSD]), amyotrophic lateral sclerosis (ALS), or other inflammatory neurological diseases (used as controls). CSF peptides/proteins were purified with magnetic beads, and directly measured by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The obtained spectra were analyzed with multivariate statistics and pattern matching algorithms. These analyses were replicated in an independent sample set of 84 patients composed of those with MS-related disorders or with other neurological diseases (the second cohort).

Results: MS-related disorders differed considerably in terms of CSF protein profiles. SP-NMOSD and SN-NMOSD, both of which fit within the NMO spectrum, were distinguishable from RRMS with high cross-validation accuracy on a support vector machine classifier, especially in relapse phases. Some peaks derived from samples of relapsed SP-NMOSD can discriminate RRMS with high area under curve scores (>0.95) and this was reproduced on the second cohort. The similarity of proteomic patterns between selected neurological diseases were demonstrated by pattern matching analysis. To our surprise, the spectral differences between RRMS and PPMS were much larger than those of PPMS and ALS.

Interpretation: Our findings suggest that CSF proteomic pattern analysis can increase the accuracy of disease diagnosis of MS-related disorders and will aid physicians in appropriate therapeutic decision-making.
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http://dx.doi.org/10.1002/ana.22633DOI Listing
May 2012

Is novel signal transducer sulfur oxide involved in the redox cycle of persulfide at the catalytic site cysteine in a stable reaction intermediate of mercaptopyruvate sulfurtransferase?

Antioxid Redox Signal 2012 Apr 11;16(8):747-53. Epub 2012 Jan 11.

Department of Environmental Medicine, Nippon Medical School, Tokyo, Japan.

Abstract In transsulfuration reaction catalyzed by rat mercaptopyruvate sulfurtransferase (MST), a stable persulfide is formed at the catalytic site cysteine Cys(247) as a reaction intermediate. The outer sulfur atom is donated by the substrate, thiosulfate, or by mercaptopyruvate. MST serves as a thioredoxin-dependent antioxidant possessing self-regulated enzymatic activity. After oxidation of persulfurated MST by treatment with hydrogen peroxide, mass spectrometric analysis showed that the outer sulfur atom of the persulfide is oxidized to form Cys-thiosulfenate (Cys-Sγ-SO(-)), Cys-thiosulfinate (Cys-Sγ-SO(2)(-)), and Cys-thiosulfonate (Cys-Sγ-SO(3)(-)). Next, sulfur acceptor substrates including reduced thioredoxin convert all modified cysteines to nonmodified cysteines. Another sulfur acceptor substrate, cyanide, also converted these cysteines via cyanolysis. Thus, sulfur oxides are suggested to release in the redox cycle of persulfide of MST.
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http://dx.doi.org/10.1089/ars.2011.4468DOI Listing
April 2012

Proteome analysis of human amnion and amniotic fluid by two-dimensional electrophoresis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

Proteomics 2006 Jan;6(1):349-63

Department of Chemistry, Seoul National University, Gwanak-gu, Seoul, Korea 151-747.

Proteome analysis by 2-DE and PMF by MALDI-TOF MS was performed on human amnion and amniotic fluid at term. Ninety-two soluble and nineteen membrane proteins were identified from amnion. Thirty-five proteins were identified from amniotic fluid. Calgranulin A and B were found in all patients infected with Ureaplasma urealyticum, but not in any of the patients without infection, indicating that they are potential markers of intrauterine infection. Identity of calgranulin A and B was confirmed by MALDI-TOF/TOF MS. This study represents the first extensive analysis of the human amnion and amniotic fluid proteome at term and demonstrates that 2-DE and MALDI-TOF MS is a useful tool for identifying clinically significant biomarkers of problematic pregnancies.
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http://dx.doi.org/10.1002/pmic.200500084DOI Listing
January 2006

Proteome analysis of human metaphase chromosomes.

J Biol Chem 2005 Apr 31;280(17):16994-7004. Epub 2005 Jan 31.

Department of Biotechnology, Graduate School of Engineering, Osaka University, Suita, Japan.

DNA is packaged as chromatin in the interphase nucleus. During mitosis, chromatin fibers are highly condensed to form metaphase chromosomes, which ensure equal segregation of replicated chromosomal DNA into the daughter cells. Despite >1 century of research on metaphase chromosomes, information regarding the higher order structure of metaphase chromosomes is limited, and it is still not clear which proteins are involved in further folding of the chromatin fiber into metaphase chromosomes. To obtain a global view of the chromosomal proteins, we performed proteome analyses on three types of isolated human metaphase chromosomes. We first show the results from comparative proteome analyses of two types of isolated human metaphase chromosomes that have been frequently used in biochemical and morphological analyses. 209 proteins were quantitatively identified and classified into six groups on the basis of their known interphase localization. Furthermore, a list of 107 proteins was obtained from the proteome analyses of highly purified metaphase chromosomes, the majority of which are essential for chromosome structure and function. Based on the information obtained on these proteins and on their localizations during mitosis as assessed by immunostaining, we present a four-layer model of metaphase chromosomes. According to this model, the chromosomal proteins have been newly classified into each of four groups: chromosome coating proteins, chromosome peripheral proteins, chromosome structural proteins, and chromosome fibrous proteins. This analysis represents the first compositional view of human metaphase chromosomes and provides a protein framework for future research on this topic.
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http://dx.doi.org/10.1074/jbc.M412774200DOI Listing
April 2005

Ultra-stable nanoparticles of CdSe revealed from mass spectrometry.

Nat Mater 2004 Feb 25;3(2):99-102. Epub 2004 Jan 25.

Center for Interdisciplinary Research, Tohoku University, Sendai, 980-8578, Japan.

Nanoparticles under a few nanometres in size have structures and material functions that differ from the bulk because of their distinct geometrical shapes and strong quantum confinement. These qualities could lead to unique device applications. Our mass spectral analysis of CdSe nanoparticles reveals that (CdSe)(33) and (CdSe)(34) are extremely stable: with a simple solution method, they grow in preference to any other chemical compositions to produce macroscopic quantities. First-principles calculations predict that these are puckered (CdSe)(28)-cages, with four- and six-membered rings based on the highly symmetric octahedral analogues of fullerenes, accommodating either (CdSe)(5) or (CdSe)(6) inside to form a three-dimensional network with essentially heteropolar sp(3)-bonding. This is in accordance with our X-ray and optical analyses. We have found similar mass spectra and atomic structures in CdS, CdTe, ZnS and ZnSe, demonstrating that mass-specified and macroscopically produced nanoparticles, which have been practically limited so far to elemental carbon, can now be extended to a vast variety of compound systems.
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http://dx.doi.org/10.1038/nmat1056DOI Listing
February 2004