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101.
Li Bao Xu Wei Sun Hong Ying Liu Li Li Wang Jun Hai Xiao Xiao Hong Yang Song Li 《中国化学快报》2010,21(11):1318-1321
<正>A serials of novel 5-substituted benzyl-2,4-diamino pyrimidine derivatives have been synthesized and evaluated as inhibitors of c-Fms kinase by the standard MTT method.The results showed that compound 15,5-[3-methoxy-4-(pyridine-3-yl)benzyl]-2,4-diamino pyrimidine,had an IC_(50) of 1.45μmol/L in inhibiting the proliferation of M-CSF-dependent myeloid leukemia cells in mice (NFS-60),which was similar with GW2580,a selective inhibitor of c-Fms kinase. 相似文献
102.
The purpose of the present study was to determine the proteins that bind to acetophenones in the liver. Immobilized p-hydroxyacetophenone (p-HAP) was used as a ligand of affinity chromatography. Analysis using sodium dodesyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) demonstrated that five polypeptides in the liver cytosolic fraction specifically bound to the p-HAP matrix. These polypeptides were digested with Lys-specific protease and used to generate peptide maps by reversed-phase high-performance liquid chromatography. Consequently, identification from a data base of protein sequences revealed that the five polypeptides were glycogen phosphorylase, cytosolic aldehyde dehydrogenase, adenosine kinase, class I alcohol dehydrogenase and glutathione S-transferase A2. In addition to p-HAP, acetylsalicylic acid also displayed a prominent ability to elute these five enzymes from the p-HAP affinity column loaded with the cytosolic fraction of the liver. Thus, p-HAP has affinities to the above liver enzymes and is a useful ligand for analysis of them. 相似文献
103.
104.
Simon L. M. Kotormán M. Szajáni B. Boross L. 《Applied biochemistry and biotechnology》1985,11(3):195-205
Rabbit muscle pyruvate kinase was immobilized by covalent attachment to a polyacrylamide support (Akrilex C) containing carboxylic
functional groups. As a result of immobilization, the pH optimum for catalytic activity shifted into a more alkaline direction.
The apparentK
m
value with phosphoenolpyruvate increased, and that with ADP slightly decreased. With respect to the stability against urea
and thermal inactivation, the immobilized pyruvate kinase seemed to be the more stable at lower urea concentrations and between
45 and 55°C. At 1.5 and 2.5M urea and at higher temperature, there were no marked differences between the soluble and the
immobilized enzyme. 相似文献
105.
Acetate kinase (EC 2.7.2.1) is involved in the wasteful production of acetate during conversion of cellulose to ethanol byClostridium thermocellum. The properties of this enzyme activity inC. thermocellum cell extracts were determined. Optimum enzyme activity was at 60 degrees C and between pH 7.5 and 9.0. In the presence of air, acetate kinase was stable to temperatures up to 60 degrees C, retaining 90% activity after 2 h, and was inactivated rapidly at higher temperatures. The enzyme exhibited a wide range of stability to pH (5.0-9.0) when incubated at 50 degrees C for 2 h. As with other acetate kinases, a divalent cation, such as Mg(2+), was required for enzyme activity. Optimum activity was observed at 20mM MgCl(2) when ATP was held constant at 10 mM. Acetate kinase activity was adversely affected by KCl, a salt commonly used in ion-exchange or affinity chromatography, with 0.3M KCl inhibiting by 50%. These results will be important in optimizing the direct microbial conversion process of cellulose to ethanol usingC. thermocellum in coculture withClostridium thermosaccharolyticum. 相似文献
106.
107.
Zhi Li Li Institute of Basic Medical Sciences Chinese Academy of Medical Sciences School of Basic Medicine Peking Union Medical College Beijing China 《中国化学快报》2009,20(2):204-206
The catalytic and signaling activities of insulin receptor kinase(IRK)are regulated by the autophosphorylation of three tyrosine residues in a cytoplasmic protein-tyrosine kinase domain at Tyro 1158,Tyro 1162 and Tyro 1163.In this study,time-course of the auphosphorylation of the core kinase(residues 978-1283)from IRK was directly investigated by online electrospray ionization mass spectrometry.It is found that two tyrosine residues were phosphorylated in reaction time range of 30 min.This study implies ... 相似文献
108.
Yong‐Zhong Du Masato Kodaka 《Journal of polymer science. Part A, Polymer chemistry》2005,43(3):562-574
A novel biotinylated and enzyme‐immobilized nanobio device was prepared with heterobifunctional composite latex particles. Hemispherical poly(glycidyl methacrylate‐co‐divinylbenzene)/polystyrene [P(GMA‐DVB)/PSt] particles with epoxy and hydroxyl groups were prepared by soap‐free seeded emulsion polymerization with P(GMA‐DVB) seed particles. Hydroxyl groups were introduced to PSt chain terminals in the seeded stage by adding 2‐mercaptoethanol as a chain‐transfer agent. To obtain the desired hemispherical structure particles, we studied the effects of the preswelling process, the type and amount of solvents added in the seeded polymerization step, the weight ratio of the secondary monomer (styrene) to the seed particle (M/P), and the type of initiators. Under suitable conditions, heterobifunctional P(GMA‐DVB)/PSt was obtained, which was confirmed by observing the binding of streptavidin–colloidal gold with transmission electron microscopy (TEM). To obtain biotinylated and enzyme‐immobilized particles, 5‐(N‐succinimidyloxycarbonyl)pentyl D‐biotinamide was first reacted with the hydroxyl group on the PSt domain of the particle. Pyruvate kinase (PK) was then directly immobilized to the biotinylated particles through a reaction with the epoxy group in the PGMA domain. The monolayer of PK on the latex particle surface was considered to be formed by covalent binding. The activity of immobilized PK was almost conserved, even after being stored at 4 °C for 48 days. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 562–574, 2005 相似文献
109.
Fiaty K Charcosset C Perrin B Couturier R Maïsterrena B 《Journal of computational chemistry》2004,25(10):1264-1276
Simulations of coupled interactions involving enzymatic reaction diffusion and electrostatic interactions were conducted under a fixed phosphatase-channel-kinase (PCK) topology oriented from the outside to the inside of a charged membrane structure. Depending on the phosphatase and kinase locations, we recently demonstrated that active transport of a phosphorylated substrate may occur via this PCK topology. The present analysis demonstrates that, if in addition to this topology, a phosphatase activity (P(1)) is also present on the inner side of the membrane, but outside the unstirred layer surrounding the inner membrane surface, then active transport of the corresponding unphosphorylated substrate may also occur. Therefore, this PCK membrane topology, which behaves as a specific ATP-dependent transporter, appears as a general topology permitting; first, on its own the active transport of a phosphorylated substrate; second, when associated with a phosphatase acting in the bulk of the receiver compartment, the active transport of the corresponding unphosphorylated substrate, that is, in most cases, the transport of an uncharged substrate. The general mathematical model given permits the active transport of a phosphorylated substrate to be analyzed (in the absence of P(1)), the active transport of an unphosphorylated substrate (in the presence of P(1)), whatever the charge distributions on both sides of the membrane surface and whatever the positions of the membrane-bound phosphatase and the membrane-bound kinase. This general model also takes into account the consumption of ATP occurring into the receiver compartment during the time course of these transport phenomena. A broad analysis of the role played by the main parameters taken into account in the model was conducted to precisely define the physicochemical conditions and the membrane topology needed for the highest active transports within the shortest time. 相似文献
110.