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1.
K Kawasaki T Tsuji K Hirase M Miyano Y Imoto M Iwamoto 《Chemical & pharmaceutical bulletin》1991,39(3):584-589
N-Terminal tripeptide analogs of fibrin alpha-chain were synthesized and their inhibitory effect on fibrinogen/thrombin clotting was examined. A new water-soluble active ester, 3-pyridinium ester, was used for the synthesis. Among the synthetic peptides, H-Gly-Pro-Arg-hexamethyleneimine exhibited the highest inhibitory effect on fibrinogen-thrombin clotting. 相似文献
2.
We studied the hydrolysis of a neuropeptide kyotorphin (L-Tyr-L-Arg) by an enkephalin-degrading aminopeptidase purified from cytosol of rat brain in vitro. The purified enzyme was homogeneous as judged by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE), gel filtration and isoelectric focusing. The aminopeptidase with an apparent molecular weight (Mr) = 98000 catalyzed the hydrolysis of Leu- and Met-enkephalins with Km values of 125 and 142 microM, respectively. The enzyme activity was inhibited by bestatin, amastatin and puromycin but not by pepstatin, leupeptin and phenylmethanesulfonyl fluoride (PMSF). Kyotorphin was degraded by the aminopeptidase at pH 7.0, and the Vmax and Km values were 9.2 mumol/min/mg protein and 95 microM, respectively. The Km value for kyotorphin was compatible to those for Leu- and Met-enkephalins. Taken together, these results suggest a possible involvement of the enkephalin-degrading aminopeptidase in cytosolic degradation of kyotorphin in neuronal cells of rat brain. 相似文献
3.
Toshiro Watanabe Tapan Kumar Mazumder Shiro Nagai Keisuke Tsuji Shigeru Terabe 《Analytical sciences》2003,19(1):159-161
A micellar electrokinetic chromatography (MEKC) method was developed for estimating the angiotensin-I converting enzyme (ACE) inhibitory activity by separating the hippuric acid liberated in the ACE reaction mixture in the presence of an inhibitor, captopril. The hippuric acid was successfully separated and detected by MEKC with a 25 mM sodium dodecyl sulfate solution in a 25 mM phosphate-50 mM borate buffer at pH 7.0; the total analysis took about 5 min. A good linear relationship was observed between the inhibitor and the peak area of hippuric acid release. No significant difference in the ACE inhibitory activity (IC50) of captopril (an antihypertensive medicine) or autolyzed-mushrooms (functional foods) was observed between the conventional method and the MEKC method. The MEKC method was found to be a useful technique for a rapid assay of the ACE inhibitory activity. 相似文献
4.
Masaharu Asano Jinhua Chen Yasunari Maekawa Takahiro Sakamura Hitoshi Kubota Masaru Yoshida 《Journal of polymer science. Part A, Polymer chemistry》2007,45(13):2624-2637
A novel process comprising the UV‐induced photografting of styrene into poly(tetrafluoroethylene) (PTFE) films and subsequent sulfonation has been developed for preparing proton‐conducting membranes. Although under UV irradiation the initial radicals were mainly generated on the surface of the PTFE films by the action of photosensitizers such as xanthone and benzoyl peroxide, the graft chains were readily propagated into the PTFE films. The sulfonation of the grafted films was performed in a chlorosulfonic acid solution. Fourier transform infrared and scanning electron microscopy were used to characterize the grafted and sulfonated membranes. With a view to use in fuel cells, the proton conductivity, water uptake, and mechanical properties of the prepared membranes were measured. Even through the degree of grafting was lower than 10%, the proton conductivity in the thickness direction of the newly prepared membranes could reach a value similar to that of a Nafion membrane. In comparison with γ‐ray radiation grafting, UV‐induced photografting is very simple and safe and is less damaging to the membranes because significant degradation of the PTFE main chains can be avoided. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2624–2637, 2007 相似文献
5.
Masaharu Ishikawa 《Topology》2004,43(1):215-232
In the present paper we generalize the divide lying in the unit disk, introduced by A'Campo, to compact, oriented, smooth surfaces, and prove a fibration theorem for generalized divides. As a consequence, we will show that, for any link L in the tangent circle bundle Y to the compact surface, there exists an additional knot K such that the link L∪K is the binding of a “positive” open book decomposition of Y. 相似文献
6.
7.
Likelihood estimation of soft-core interaction potentials for Gibbsian point patterns 总被引:3,自引:3,他引:0
Yosihiko Ogata Masaharu Tanemura 《Annals of the Institute of Statistical Mathematics》1989,41(3):583-600
The likelihood method is developed for the analysis of socalled regular point patterns. Approximating the normalizing factor of Gibbs canonical distribution, we simultaneously estimate two parameters, one for the scale and the other which measures the softness (or hardness), of repulsive interactions between points. The approximations are useful up to a considerably high density. Some real data are analyzed to illustrate the utility of the parameters for characterizing the regular point pattern. 相似文献
8.
Yasuo Kameda Motoya Sasaki Masahiro Yaegashi Kosuke Tsuji Shingo Oomori Shuji Hino Takeshi Usuki 《Journal of solution chemistry》2004,33(6-7):733-745
Time-of-Flight (TOF) neutron diffraction measurements have been carried out on aqueous 8 mol% sodium acetate solutions in D2O. Scattering cross sections that were observed for sample solutions involving 12C/13C and H/D isotopically substituted acetate ions were used to derive the first-order difference functions, ΔH(Q) and ΔC(Q), and corresponding distribution functions, G H(r;r) and G C(r;r), which describe the environmental structure around the methyl and the carboxyl groups within the acetate ion, respectively. Structural parameters concerning the first hydration shell of the carboxyl group within the acetate ion were obtained through the least squares fit to the observed intermolecular difference function, ΔC inter(Q). The nearest neighbor C O...D W1 (CO: carboxyl carbon atom, DW1: water deuterium atom) distance, r(C O...D W1 ), and the angle, ∠ C O ...D W1 -O W (O W : water oxygen atom), were determined to be 2.63(1) Å and 120(1)°, respectively. The coordination number, n(C O ...D W1 ), was obtained to be 4.0(1). These results are consistent with the hydration structure in which water molecules in the first hydration shell of the carboxyl group are hydrogen-bonded with oxygen atoms of the carboxyl group. 相似文献
9.
Kiitiro Utimoto Yukio Wakabayashi Yuho Shishiyama Masaharu Inoue Hitosi Nozaki 《Tetrahedron letters》1981,22(43):4279-4280
Title transformation is accomplished by the catalytic action of SnCl2 or BF3·OEt2 Lithio derivative of 2,2-dimethoxyacetonitrile is used as synthetic equivalent of methyl lithioformate. 相似文献
10.
Several transition metal salts were found to catalyze aza-Michael reactions of enones with carbamates efficiently. The catalytic activity was strongly dependent on the nature of the metal salts. While conventional Lewis acids such as BF(3).OEt(2), AlCl(3), or TiCl(4) showed lower activity, group 7-11 transition metal salts in higher oxidation states such as ReCl(5), Fe(ClO(4))(3).9H(2)O, RuCl(3).nH(2)O, OsCl(3).3H(2)O, RhCl(3).nH(2)O, PtCl(4).5H(2)O, or AuCl(3).H(2)O exhibited higher catalytic activity. [reaction: see text] 相似文献