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排序方式: 共有857条查询结果,搜索用时 15 毫秒
851.
Plant metabolism research has experienced a second golden age resulting from synergies between genome-enabled technologies and classical biochemistry. The rapid rate at which genomics data are being accumulated creates increased needs for robust metabolomic technologies and fast and accurate methods for identifying the activities of enzymes. 相似文献
852.
Zhao Xingtang Liang Nansong He Liming Yu Lei Cao Yang Xia Dean Xiao Ying Zhang Guiqin Zeng Fansuo Zhan Yaguang 《New Forests》2021,52(6):921-942
New Forests - Biomass-based carbon (C) stock estimation is the most accurate method for estimating the C stock in forestry. To accurately estimate the Manchurian ash (Fraxinus mandshurica Rupr.) C... 相似文献
853.
Regulation of an enzyme by phosphorylation at the active site 总被引:22,自引:0,他引:22
J H Hurley A M Dean J L Sohl D E Koshland R M Stroud 《Science (New York, N.Y.)》1990,249(4972):1012-1016
The isocitrate dehydrogenase of Escherichia coli is an example of a ubiquitous class of enzymes that are regulated by covalent modification. In the three-dimensional structure of the enzyme-substrate complex, isocitrate forms a hydrogen bond with Ser113, the site of regulatory phosphorylation. The structures of Asp113 and Glu113 mutants, which mimic the inactivation of the enzyme by phosphorylation, show minimal conformational changes from wild type, as in the phosphorylated enzyme. Calculations based on observed structures suggest that the change in electrostatic potential when a negative charge is introduced either by phosporylation or site-directed mutagenesis is sufficient to inactivate the enzyme. Thus, direct interaction at a ligand binding site is an alternative mechanism to induced conformational changes from an allosteric site in the regulation of protein activity by phosphorylation. 相似文献
854.
855.
DR Stewart D Sprinzak CM Marcus CI Duruoz JS Harris 《Science (New York, N.Y.)》1997,278(5344):1784-1788
The ground and excited state spectra of a semiconductor quantum dot with successive electron occupancy were studied with linear and nonlinear magnetoconductance measurements. A direct correlation was observed between the mth excited state of the N-electron system and the ground state of the (N + m)-electron system for m up to 4. The results are consistent with a single-particle picture in which a fixed spectrum of energy levels is successively filled, except for a notable absence of spin degeneracy. Further departures from the single-particle picture due to electron-electron interaction were also observed. Magnetoconductance fluctuations of ground states show anticrossings where wave function characteristics are exchanged between adjacent levels. 相似文献
856.
Scintigraphy of normal mouse ovaries with monoclonal antibodies to ZP-2, the major zona pellucida protein 总被引:1,自引:0,他引:1
The zona pellucida is an extracellular glycocalyx, made of three sulfated glycoproteins, that surrounds mammalian oocytes. Parenterally administered monoclonal antibodies specific for ZP-2, the most abundant zona protein, localize in the zona pellucida. When labeled with iodine-125, these monoclonal antibodies demonstrate a remarkably high target-to-nontarget tissue ratio and provide clear external radioimaging of ovarian tissue. 相似文献
857.
Inherited diseases of Australian Holstein-Friesian cattle 总被引:1,自引:1,他引:0