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221.
222.
223.
Steric effects in the acylation of alpha-chymotrypsin 总被引:1,自引:0,他引:1
224.
Wayne Fife 《Anthropology & education quarterly》1998,29(1):142-143
Embodying Colonial Memories: Spirit Possession, Power, and the Hauka in West Africa. Paul Stoller New York: Routledge, 1995. 226 pp. 相似文献
225.
MS Nandhu Jes Paul Korah P Kuruvilla Anitha Malat Chinthu Romeo CS Paulose 《Journal of biomedical science》2011,18(1):5
Parkinson's disease is characterized by progressive cell death in the substantia nigra pars compacta, which leads to dopamine
depletion in the striatum and indirectly to cortical dysfunction. Increased glutamatergic transmission in the basal ganglia
is implicated in the pathophysiology of Parkinson's disease and glutamate receptor mediated excitotoxicity has been suggested
to be one of the possible causes of the neuronal degeneration. In the present study, the effects of serotonin, gamma-aminobutyric
acid and bone marrow cells infused intranigrally to substantia nigra individually and in combination on unilateral 6-hydroxydopamine
induced Parkinson's rat model was analyzed. Scatchard analysis of total glutamate and NMDA receptor binding parameters showed
a significant increase in Bmax (P < 0.001) in the cerebral cortex of 6-hydroxydopamine infused rat compared to control. Real Time PCR amplification of NMDA2B,
mGluR5, bax, and ubiquitin carboxy-terminal hydrolase were up regulated in cerebral cortex of 6-hydroxydopamine infused rats
compared to control. Gene expression studies of GLAST, ά-Synuclien and Cyclic AMP response element-binding protein showed
a significant (P < 0.001) down regulation in 6-OHDA infused rats compared to control. Behavioural studies were carried out
to confirm the biochemical and molecular studies. Serotonin and GABA along with bone marrow cells in combination showed reversal
of glutamate receptors and behaviour abnormality shown in the Parkinson's rat model. The therapeutic significance in Parkinson's
disease is of prominence. 相似文献
226.
Bruce R. DeMark Bruce M. Benjamin Thomas H. Fife 《Archives of biochemistry and biophysics》1983,223(2):360-368
The effects of the inhibitors trimethylacetyl phosphate and cAMP have been determined in reactions catalyzed by d-glyceraldehyde-3-phosphate dehydrogenase. These inhibitors must influence the oxidation of aldehydes through substrate dependent co-operative conformational changes. Both trimethylacetyl phosphate and cAMP give sigmoidal vs (I) plots in oxidation of glyceraldehyde 3-phosphate, but exert linear competitive effects on the acyl phosphatase site in acylation reactions of β-(2-furyl) acryloyl phosphate. The linear inhibition in the latter reactions indicates that one inhibitor molecule is bound per active site. Hydride transfer to NAD+ is the ratedetermining step in oxidation of benzaldehyde to an acylenzyme, as shown by the threefold decrease in Vmax without change in Km when 1-deuterobenzaldehyde is the substrate; it is very likely this step that is affected by acyl phosphate inhibitors. Plots of vs cAMP concentration for oxidation of benzaldehyde at a series of trimethylacetyl phosphate concentrations are parallel at concentrations of acyl phosphate less than 0.00625 m, which demonstrates that binding of the inhibitors is mutually exclusive. However, at higher concentrations of trimethylacetyl phosphate, the slopes are affected, which shows that both inhibitors are then binding. Thus, the binding of high concentrations of acyl phosphate must result in a conformational change of the enzyme that permits binding of both inhibitors. A number of conformations with different kinetic properties are formed with the various substrate and inhibitor combinations. In reactions of muscle d-glyceraldehyde-3-phosphate dehydrogenase, binding of these inhibitors is best explained in terms of induced fit and a sequential model of conformational changes. 相似文献
227.
228.
E L Ferroni E T Harper W K Fife 《Biochemical and biophysical research communications》1991,176(1):511-516
Rabbit muscle aldolase was found to be inactivated in a slow, reversible manner by D-erythrulose 1-phosphate. This compound combined rapidly and reversibly with the enzyme to form an initial complex, which then only slowly (ki = 0.28 min-1) converted to a kinetically more stable form. This stable enzyme-ligand form was inactive toward the normal substrate of aldolase, fructose 1,6-bisphosphate. The inactive enzyme-ligand complex, however, could be decomposed (kr = 0.0041 min-1) to yield active enzyme once again by incubation in a solution devoid of D-erythrulose 1-phosphate. 相似文献