JMSSJ On-line Abstracts, Vol.47, No.3 (1999)
Yuichi SUGIYAMA*a), Hiroshi SUZUKIa), and Kiyomi ITOb)
(*a)Graduation School of Pharmaceutical Sciences, University of Tokyo, 7-3-1 Hongo,
Bunkyo-ku, Tokyo 113-0033, Japan, b)School of Pharmaceutical Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan)
J. Mass Spectrom. Soc. Jpn., 47(3), 97-109, 1999
Recently, attempts have been made to synthesize rapidly very large numbers of compounds and identify promising drug candidates in terms of both their pharmacological activity and pharmacokinetic features during the early stages of screening (high throughput screening). In drug development, therefore, the importance of the extrapolationandpredictionofpharmacokineticsinhumanshasincreasedandphysiologically-basedpharmacokinetics has played an important role in this.
It has become possible to predict in vivo pharmacokinetics in humans if accurate data are available on in vitro drug metabolism, plasma membrane transport, and protein binding and if these data can be combined with physiological parameters such as hepatic blood flow etc. Recent findings are summarized for the quantitative prediction of the hepatic metabolic clearance from in vitro studies using human liver microsomes or P450 isozyme recombinant systems. Furthermore, a method is proposed to predict pharmacokinetic alterations caused by drug-drug interactions based on in vitro metabolic inhibition studies using human liver microsomes or human enzyme expression systems.
Biliary or urinary excretion of drugs has been shown to be mediated by various transporters. Some transporters have been shown to be involved also in the efflux of various compounds through the blood-brain barrier (BBB). Examples of the recent studies showing the relevance of transporters in pharmacokinetics are given and the prediction of BBB permeability is also discussed. In future, these transport characteristics of the drug and the possibility of drug-drug interactions involving transport will also need to be taken into consideration for more strategic and efficient drug development.
Yoshihisa KUDO*a), Takeshi NAKAMURAa), Kyoko NAKAMURAa), Takae HIRASAWAb), and Ikuko EZAWAb)
(*a)School of Life Science, Tokyo University of Pharmacy and Life Science, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan, b)Graduate School of Human Life Sciences, Japan Women's University, Mejirodai, Bunkyo-ku, Tokyo 112-8681, Japan)
J. Mass Spectrom. Soc. Jpn., 47(3), 110-114, 1999
Local ischemia in the specific region of brain has been regarded as one of major causes for senile dementia. Transient increase in intracellular Ca2+ concentration ([Ca2+]i) of neuronal cells in hippocampal CA1 region has been found to result in so called delayed neuronal cell death. Increase in [Ca2+]i was also induced by administration of parathyroid hormone (PTH), an important hormone for plasma Ca2+ level. The hormone in a concentration as low as 10 pM caused neuronal cell death in hippocampal organotypic culture within one week. Since plasma PTH level tends to increase in elderly, PTH should be paid attention to be one of the risk factors for senile dementia. Protection of neuronal cells against the Ca2+ overloading may be one of the important treatment for the rescuing the neurons from the death due to senescence.
Ikumi TAMAI*
(*Faculty of Pharmaceutical Science, Kanazawa University, 13-1 Takara-machi, Kanazawa 920-0934, Japan)
J. Mass Spectrom. Soc. Jpn., 47(3), 115-122, 1999
According to the recent advances in the molecular biological studies for biological membrane transport, a significant contribution of carrier-mediated transport mechanism in the intestinal absorption, tissue distribution, and renal and hepatic excretion for various drugs has been suggested. Oligopeptide transporter PepT1 is expressed at the brush-border membrane of intestinal epithelial cells and has a predominant role in intestinal absorption of natural di- and tripeptides. Interestingly PepT1 has broad substrate specificity and accepts various peptide mimetic drugs such as 
-lactam antibiotics, angiotensin converting enzyme inhibitors, renin inhibitors and anticancer drug. Accordingly, PepT1 is expected to be used for improvement of intestinal absorption of poorly absorbed drugs by derivation of the drugs to peptide mimetics. When transport of L-phenylalanylpeptide derivative (L-dopa-L-Phe) of L-dopa, an antiperkinsonian, across intestinal epithelial-like Caco-2 cells was measured, increased transport by utilization of PepT1 was demonstrated, suggesting an improvement of intestinal absorption by peptide-derivation strategy. Furthermore, the similar transport activity with PepT1 was demonstrated in certain tumor cells. Accordingly, delivery of peptide-mimetic anticancer drug to tumor by utilization of peptide transporter activity was also suggested. Since these physiological transporters are tissue and substrate specific, it is advantageous to improve pharmacokinetic features of drugs by utilization of these transporters.
Seiji YOSHIMURA*
(*Exploratory Research Laboratories, Fujisawa Pharmaceutical Co., Ltd., 5-2-3 Tokodai, Tsukuba 300-2698, Japan)
J. Mass Spectrom. Soc. Jpn., 47(3), 123-128, 1999
FR139317, the potent endothelin A receptor (ETA) antagonist, was designed and synthesized using NMR conformational analysis of WS7338B, ETA antagonist isolated from Streptomyces sp.
FR167233, the potent inhibitor against type II phospholipase A2 (PLA2), was synthesized based on the structure of WA8242B, the inhibitor isolated from Streptomyces sp., using the computational structural analysis of the complex of type II PLA2 and WA8242B.
The strategies for the drug design of FR139317 or FR167233 can be applied for increasing number of natural products as the advancement of organic chemistry.
Hideki TSUJISHITAa),+ , Yasuyuki HIRAMATSUb), and Hirosato KONDO*a)
(*a)Nippon-Organon Research & Development Laboratories, 1-5-90 Tomobuchi-cho, Miyakojima-ku, Osaka 534-8666, Japan, a),+ Present address: Bayer Yakuhin Research Center Kyoto, 6-5-1-3 Kunimudai, Kizu-cho, Soraku-gun, Kyoto 619-0216, Japan)
J. Mass Spectrom. Soc. Jpn., 47(3), 129-134, 1999
A design of non-carbohydrate selectin blockers based on a carbohydrate compound is described. We first investigated the mode of interaction between selectin and its carbohydrate ligand, GSC-150. GSC-150 has a sulfated sugar unit and a branched long alkyl chain (B-30). From a molecular dynamics simulation of the complex of GSC-150 with E-selectin in water, we found the essential three functional groups of GSC-150 necessary for binding toward selectin: namely, the negatively-charged sulfate, the fucose, and B-30. Especially, B-30 would play an important role in the tight hydrophobic interaction with selectin. The lactose unit of GSC-150 may serve as a scaffold that keeps those functional groups to their proper orientation. Next we searched for another scaffold, and found that the modified Ser-Glu dipeptides could be good surrogates. They are about 50 to 100-fold more potent blocker than GSC-150. A detailed analysis of their binding mode suggested that the dipeptide backbone could adopt type-II -turn conformation, a minor subtype of -turn, in their bound state. This type-II -turn would be necessary to fix the critical functional groups in the dipeptides to their proper orientation.
Masaji ISHIGUROH*
(*Suntory Institute for Bioorganic Research, Shimamoto, Osaka 618-8503, Japan)
J. Mass Spectrom. Soc. Jpn., 47(3), 135-139, 1999
Computational methods for drug design and its application for structure-based drug design using crystallographic data and NMR solution structural data were briefly described in view of interaction of ligands with or without structures of the target receptors. Analysis of the hydrolytic mechanism of -lactamases whose 3D stuctures has been known led to understanding a specific recognition of -lactam antibiotics and to design of a new candidate for anti-MRSA antibiotics. Conformational analysis of peptide derivatives whose receptor structures have not known is the other example for design of new skeletons of nonpeptide compounds. Receptor-bound structure analysis of antagonist or agonist peptides suggested different conformations of the peptides. This may be due to a different receptor structure as a consequence of a large structural change of receptors upon binding of agonists.
Kenzo HIRAOKA*
(*Faculty of Engneering, Yamanashi University, 3-11 Takeda 4-chome, Kofu 400-8511, Japan)
J. Mass Spectrom. Soc. Jpn., 47(3), 140-148, 1999
Comments on the mechanisms for the formation of multiply-charged ions from the electrosprayed charged liquid droplets were given. The excess charges in the charged droplets mainly locate on the surface of the droplets. Evaporation of solvent from the parent charged liquid droplets produced from the Taylor cone leads to uneven fission. The secondary droplets thus formed become much more highly-charged by the slip-over of the charged skin of the parent droplets. The excess charges donated in the secondary charged droplets result in the formation of highly charged gas-phase analyte ions through evaporation of the solvent and added acids or bases in the droplets. The ion formation by FAB is mainly due to the explosive evaporation of matrix element induced by the shock wave and thus the analyte ions observed generally represent those solvated in the matrix. This is why the number of excess charges in the analyte ions formed by FAB is smaller than those formed by electrospray.
Yasuhide NAITO*
(*The Institute of Physical and Chemical Research (RIKEN), (2-1 Hirosawa, Wako-shi 351-0198, Japan)
J. Mass Spectrom. Soc. Jpn., 47(3), 149-159, 1999
Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) is considered as one of the best option for biological application fields, where an extreme analytical performance in a very high mass region is increasingly demanded. This paper illustrates the characteristics of FT-ICR MS, involving the advantage and disadvantage, especially in being used for biological mass spectrometry. The contents include the origin of the ultra-high resolving power, the versatility of the ion trapping technique, and the congeniality to the advanced ionization methods for biomolecules.
Tsutomu SUZUKI*a), Takeo SUZUKIa), Takuya UEDAa), b), and Kimitsuna WATANABEb)(*a)Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan, b)Department of Integrated Biosciences, Guraduate School of Frontier Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan)
J. Mass Spectrom. Soc. Jpn., 47(3), 168-176, 1999
It has been known that RNA has a lot of modified nucleosides which are post-transcriptionally introduced by specific enzymes. Modified nucleosides play an important role in the RNA function. In the case of transfer RNA, modified uridine at the first letter of anticodon is thought to participate in the selection of cognate codon so as to ensure the accurate translation. In this report, we tried to detect unknown species of modified uridine from bovine mitochondrial tRNAs by ESI/iontrap mass spectrometer with a new method for derivatizing the modified uridines with CMC [N-cyclohexyl-N'-b-(4-methylmorpholinium)ethylcarbodiimide].
Yuji NISHIZAWA*a) and Hiroyuki MATSUMOTOb)
(*a)Department of Anatomy, School of Medicine, Nagoya University, 65 Tsurumi-cho, Showa-ku, Nagoya 466-8550, Japan, b)Department of Biochemistry and Molecular Biology, and NSF EPSCoR Oklahoma Biotechnology Network Laser Mass Spectrometry Facility, The University of Oklahoma Health Sciences Center, P.O. Box 26901, Oklahoma City, OK 73190, U.S.A.)
J. Mass Spectrom. Soc. Jpn., 47(3), 177-182, 1999
To assemble a catalogue of proteins expressed in mammal photoreceptor cells, following experimental strategy was carried out: the preparation of bovine photoreceptor cell monolayer (PCL) and the methodology for analyzing proteins on 2-D gels and mass spectrometry. Trypsin digested peptides were separated by HPLC and analyzed by a matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometer. Some peptides were sequenced by Edman degradation. To identify the proteins, each peptide-mass data set was referred to on-line peptide-mass fingerprinting database. To standardize the 2-D gel profile, we determined the pI and molecular weight coordinates of some of the major proteins in the photoreceptor cells by running internal proteins marker and by considering theoretical values based on the known sequences. Fourteen major 2-D gel spots were identified and listed to our catalogue.
Toshiyuki KOSAKA*a), Sachiko HORIUCHIa), and Takemichi NAKAMURAa)
(*a)Analytical and Metabolic Research Laboratories, Sunkyo Co., Ltd. 2-58 Hiromachi 1-chome, Shinagawa-ku, Tokyo 140-8710, Japan)
J. Mass Spectrom. Soc. Jpn., 47(3), 183-190, 1999
Proteome analysis exploits advanced two-dimensional gel electrophoresis (2-DE) technology and efficient methods for protein identification supported by modern mass spectrometry, and now becomes a very common tool for functional genomics, drug-target discovery, etc. In this paper, a procedure of proteome analysis is described with an example of the analysis of varied protein expression related to a disease. The protein expression patterns in Zucker diabetic fatty (ZDF) rat, which is a model of non-insulin-dependent diabetes mellitus, and lean ZDF control rat livers were displayed with 2-DE and the differences were analyzed. Two proteins which showed significant change in the protein expression, were identified by a combination of in-gel digestion, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and database search with peptide-mass fingerprinting.
Yasuo SUDA*
(*Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan)
J. Mass Spectrom. Soc. Jpn., 47(3), 206-210, 1999
In our research projects on phosphorylated or sulfated glycoconjugates obtained from natural sources or by syntheses, the structural elucidation of the small amount of compound is extremely important. Although mass spectrometry is the first choice for the identification, we face some times problems in the conventional negative-ion mode mass spectrometry. The ESI/TOF MS (MarinerTM) in the negative-ion mode has solved our problems in many cases. This report shows several examples of mass spectra obtained in the negative-ion mode using MarinerTM.
Zenzaburo TOZUKA*
(*Biopharmaceutical and Pharmacokinetics Research Laboratories, Fujisawa Pharmaceutical Co., Ltd., 1-6 Kashima 2-chome, Yodogawa-ku, Osaka 532-8514, Japan)
J. Mass Spectrom. Soc. Jpn., 47(3), 229-245, 1999
The quantitative analysis is the base of clinical pharmacokinetics, pharmacokinetics, toxicokinetics, and pharmacodynamics. The pretreatment is important for the quantitative analysis, because the recovery of the pretreatment for the quantitative analysis affects the biological concentration of the drug. The pretreatment has many functions such as the change of time, place, and men, etc. from sampling to the analysis. The stability and adsorption of the drug during the pretreatment affects the quantitative values. The biological matrix such as plasma, urine, bile, feces, and tissues interferes the analysis. The organic solvents and water is purified before using for the pretreatment. The plastic containers for sampling and stocking, the extraction tube and HPLC, tube contains the interfere peaks such as dioctylphthalate. The technique of the pretreatment such as the liquid-liquid extraction, solid phase extraction, open column extraction, TLC, HPLC, and LC/MS are shown. The maintenance of LC/MS affects the quantitative values. The problems and the countermeasure of the pretreatment for the quantitative analysis are described.
