Journal of the Mass Spectrometry Society of Japan
Online ISSN : 1880-4225
Print ISSN : 1340-8097
ISSN-L : 1340-8097
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Volume 45, Issue 3
Displaying 1-16 of 16 articles from this issue
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COMMENTARY
COMMENTARY
  • Performance and Limitations of Quadrupolar and FTICR Ion Traps
    Arnd INGENDOH, Michael SCHUBERT, Roland JERTZ, Gökhan BAYKUT, Pau ...
    1997 Volume 45 Issue 3 Pages 247-264
    Published: 1997
    Released on J-STAGE: July 20, 2007
    DOIhttps://doi.org/10.5702/massspec.45.247
    JOURNAL FREE ACCESS
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    Quadrupolar and electromagnetic (FTICR) ion traps generated a strong attractive power for the biological MS community since they can be used in combination with the external sources ESI and MALDI. In general, ion traps are most interesting because of a capability which differentiates them from all other mass spectrometers: the storage of ions. Due to this fact, their powerful flexibility in performance is quite unique among all mass analyzers. Once the ions are stored, they can be manipulated in many different ways. Particularly multistage MS/MS experiments which require additional, spaceous analyzer hardware in other mass spectrometric techniques, can be performed subsequently in time by using exactly the same instrumental setup. While the quadrupolar ion trap mainly convinces by its ease of operation and the low cost at full MS/MS capabilities, FTICR instruments are truely unsurpassed in performance among all mass spectrometers in terms of resolution, mass accuracy and MSn capabilities. In this report, both techniques will be discussed with special regards to typical applications of biological and biochemical analysis which at the same time reveal capabilities and limitations of ion traps.
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REVIEW
  • Combinatorial Chemistry
    Toshiro SUENAGA
    1997 Volume 45 Issue 3 Pages 265-288
    Published: 1997
    Released on J-STAGE: July 20, 2007
    DOIhttps://doi.org/10.5702/massspec.45.265
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    Combinatorial chemistry is a novel and innovative technology to generate and screen a large number of compounds simultaneously. Traditionally, new drag lead compounds were discovered by screening sources of natural products or collections of compounds from chemical synthesis in pharmaceutical companies. Recently, computer assisted structure-activity based approaches enable the “rational drug design” to avoid laborious and serendipitous synthesis. More recently, combinatorial chemistry–sometimes referred to as “irrational drug design”-has emerged and is believed to give a big advantage over traditional methods.
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COMMENTARIES
  • Drug Discovery from Natural Products and Dereplication
    Takeshi OGITA
    1997 Volume 45 Issue 3 Pages 289-294
    Published: 1997
    Released on J-STAGE: July 20, 2007
    DOIhttps://doi.org/10.5702/massspec.45.289
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    Drug discovery from natural products is often hampered by their intrinsic nature. Namely, extracts of natural sources are usually complex mixtures and laborious purification is eventually required. They sometimes contain non-specific active compounds which may lead to false positive hits. Therefore, much effort has been paid to overcome these difficulties, for example, by developing innovative screening program, establishing a robotic system applicable for a mass screening and/or scrutinizing novel natural sources. Among them, the importance of efficient dereplication is getting higher since the probability of discovering novel bioactive compounds is declining as the number of known compounds increases. This paper summarizes and discusses the dereplication strategies including biological, taxonomic, and chemical methods.
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  • Dereplication of Natural Products Using LC/MS
    Nobuharu SHIGEMATSU
    1997 Volume 45 Issue 3 Pages 295-300
    Published: 1997
    Released on J-STAGE: July 20, 2007
    DOIhttps://doi.org/10.5702/massspec.45.295
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    Development of analytical instruments, especially of LC/MS, led us to a quick and effective identification of known natural compounds. Dereplication is an important concept in the development of useful medicines that are derived from natural products. Separation, analysis, and searching are important factors for the dereplication.
    This paper establishes a method for doing the dereplication and shows the know-how of each step.
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  • The Efficient Identification Method of Known Compounds for Natural Products Screening
    Noboru NAKAYAMA
    1997 Volume 45 Issue 3 Pages 301-307
    Published: 1997
    Released on J-STAGE: July 20, 2007
    DOIhttps://doi.org/10.5702/massspec.45.301
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    Recently, the screening of many samples for drug discovery could be managed in a short time by a high throughput screening method. Unfortunately, natural products are not suitable for the high throughput screening method, but natural products are appealing as a screening source because of their abundant diversity. Accordingly, its very important to establish a method for doing natural product screening efficiently. An efficient elimination or identification method of known compounds for natural product screening is discussed, and our identification method for natural products is also reviewed.
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COMMENTARIES
  • Determination of Molecular Weight and Structure of Drug Metabolites Using Mass Spectrometry
    Kouji IWATANI
    1997 Volume 45 Issue 3 Pages 309-323
    Published: 1997
    Released on J-STAGE: July 20, 2007
    DOIhttps://doi.org/10.5702/massspec.45.309
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    Mass spectrometry (MS) has been used extensively because of the development of ionization methods followed by their improvement and the solution of analytical problems in inorganic and organic chemistry, biochemistry and medicine. MS has become a powerful and standard method for the identification, structural determination and elucidation of wide variety of compounds, when it is employed in complementary with other physical methods such as nuclear magnetic resonance (NMR), X-ray diffraction and infrared spectroscopy (IR). However, there are still many problems to be solved in MS. In this paper, I proposed the improved methods which may be helpful for solving the problems.
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  • Role of Sector-Based Tandem Mass Spectrometry in Structural Elucidation of Natural Products
    Takemichi NAKAMURA
    1997 Volume 45 Issue 3 Pages 325-339
    Published: 1997
    Released on J-STAGE: July 20, 2007
    DOIhttps://doi.org/10.5702/massspec.45.325
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    Unlike NMR, mass spectrometry seems to be used as a supplementary method in general, rather than a critical tool in the structural analysis of “truly unknown” compounds, such as newly isolated biologically active natural products. One of the reasons is that instruments designed for structural analysis tend to be relatively expensive and hard to maintain and/or operate by natural product chemists, until recently. However, another, and more essential reason is underlying the nature of mass spectrometric structural analysis, i.e., the process of analysis relies on non-quantitative, highly empirical, and hard-to-generalize fragmentation rules, and is difficult to explain deductively to non-experts. It may also be believed to be difficult to extract structural information from high-energy collision induced dissociation (CID) mass spectra generated by sector-based tandem mass spectrometers, which are basically rich in structural information but hard to interpret. In this situation, we have learned that, at least in some cases, tandem mass spectrometry (MS/MS) can be used as an aid to extract vital structural information unambiguously and can be used for building unknown structures rationally, without using inspiration of an expert. In this paper, examples from our experiences in structural elucidation of natural products are shown and following points, (1) how MS/MS can help extracting crucial structural information from complex structures and (2) how MS/MS can be used for rational building of a new structure, are focused. (3) A possible role of high-energy-CID MS3 in structural elucidation of natural products is also discussed.
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INTEGRATED PAPER
COMMENTARY
  • Peptide and Protein Epitope Mapping by Mass Spectrometry
    Naoyuki YAMADA
    1997 Volume 45 Issue 3 Pages 355-366
    Published: 1997
    Released on J-STAGE: July 20, 2007
    DOIhttps://doi.org/10.5702/massspec.45.355
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    Antigenic determinants, also called epitopes, constitute the region of the protein in intimate contact with the antigen-binding region of an antibody. Epitopes are typically classified as being either continuous or discontinuous. A variety of methods have been applied to the study of monoclonal antibody (mAb)-antigen interactions and the characterization of their respective epitopes. Here we introduce some new methods of peptide and protein epitope mapping by mass spectrometry.
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REGULAR PAPER
  • Quantitative Method for Hydroxytestosterone by GC/MS and Its Application for Measurement of P450 Enzyme Activity
    Noriko WATANABE, Rika GODA, Hisashi OCHIAI, Kouwa YAMASHITA
    1997 Volume 45 Issue 3 Pages 367-375
    Published: 1997
    Released on J-STAGE: July 20, 2007
    DOIhttps://doi.org/10.5702/massspec.45.367
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    Cytochrome P450 (Cyt. P450) is capable of metabolizing a wide range of endogenous and xenobiotic compounds. The metabolism of testosterone has been used to probe into Cyt. P450 isoenzyme activities of rat liver preparations in vitro. Then we studied the quantitation method of hydroxytestosterone by GC/MS for the measurement of Cyt. P450 isoenzyme activities.
    Testosterone and 4 kinds of hydroxytestosterones (2α, 6β, 16α, and 16β-OH) were derivatized into the ethoxime-dimethylisopropylsilyl ether derivatives and separated completely on fused silica capillary column. Linearity of the method was established over the concentration range of 0.1-20 ng/sample for 2α, 6β, and 16α-hydroxytestosterones.
    The present method enabled the measurement of testosterone 2α and 6β-hydroxylation in a trace amount of rat liver homogenate. And the method revealed the relationship between the change in actual isoenzyme activity and inducer treatment such as phenobarbital and dexamethasone. The method is applicable to the measurement of wide variety of Cyt. P450 isoenzyme activities.
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REVIEW
  • Know-How of the High Sensitivity Quantitative Analysis of Drugs by LC/API/MS
    Zenzaburo TOZUKA
    1997 Volume 45 Issue 3 Pages 377-399
    Published: 1997
    Released on J-STAGE: July 20, 2007
    DOIhttps://doi.org/10.5702/massspec.45.377
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    LC/API/MS enables quantitative analysis of drugs with high sensitivity. In order to obtain fine mass spectra, know-how for high sensitivity analysis is required. A stable spray can produce stable ionization for LC/MS analysis. It is also necessary to purify the samples for quantitation with high sensitivity. In addition to those, adequate analytical conditions of HPLC, LC/API/MS interface, and SIM (or SRM/MS) are important for analysis. Fragmentations observed in EI, CI, FAB, and LC/ESI mass spectrometry gave us hints for the selections of mass numbers for SRM analysis. LC/MS/MS analysis of enables quatitation of pg/ml level of drugs in plasma.
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COMMENTARY
  • Quantitative Method for Biological Active Substance in Biological Samples by Hyphenated MS Techniques:
    What is the key point?
    Nariyasu MANO, Yoshiya ODA, Naoki ASAKAWA
    1997 Volume 45 Issue 3 Pages 401-415
    Published: 1997
    Released on J-STAGE: July 20, 2007
    DOIhttps://doi.org/10.5702/massspec.45.401
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    Mass spectrometry (MS) has been recognized as an integral method in biological research and our ability to analyze a wide variety of biologically relevant molecules has been greatly advanced by MS. Highly sensitive, highly selective, and reproducible hyphenated MS (GC/MS, LC/MS) or MS/MS method is necessary to get high quality information. We show that the optimization of MS interface is very important for high sensitivity. Chromatography techniques are also indispensable to distinguish identical mass substances. In addition to avoiding adsorption and contaminants problem, our optimized conditions have resulted in a suitable quantitative analysis method for endogenous biological active substances in biological materials.
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INTEGRATED PAPER
  • Chiral Recognition in Host-Guest Complexation Determined by FAB Mass Spectrometry
    Masami SAWADA
    1997 Volume 45 Issue 3 Pages 439-458
    Published: 1997
    Released on J-STAGE: July 20, 2007
    DOIhttps://doi.org/10.5702/massspec.45.439
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    Chiral recognition in host-guest complexation and the related systems detected by FAB mass spectrometry was reviewed. Our newly developed methodology, which is called as “enantiomer-labeled guest method”, is largely explained on the basis of both fundamentals and applications. Emphasis is put on the facts that chiral recognition abilities of various hosts toward various guests are easily and reliably determined by the method and the results are straightforwardly compared with each other, or more importantly, with those from thermodynamics in solution using - ΔΔGenan (kcal/mol) values. The chiral hosts examined contain several synthetic crown ethers, natural ionophores, and carbohydrate derivatives. The chiral guests examined contain several amino acid esters and amino acids. Basic concept of the forthcoming “enantiomer-labeled host method” is also stated briefly.
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REGULAR PAPERS
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