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Interaction of rat glutathione S-transferases 7-7 and 8-8 with gamma-glutamyl- or glycyl-modified glutathione analogues. 总被引:1,自引:0,他引:1 下载免费PDF全文
A E Adang D J Meyer J Brussee A Van der Gen B Ketterer G J Mulder 《The Biochemical journal》1989,264(3):759-764
Analogues of GSH in which either the gamma-glutamyl or the glycyl moiety is modified were synthesized and tested as both substrates for and inhibitors of glutathione S-transferases (GSTs) 7-7 and 8-8. Acceptor substrates for GST 7-7 were 1-chloro-2,4-dinitrobenzene (CDNB) and ethacrynic acid (ETA) and for GST 8-8 CDNB, ETA and 4-hydroxynon-trans-2-enal (HNE). The relative ability of each combination of enzyme and GSH analogue to catalyse the conjugation of all acceptor substrates was similar with the exception of the combination of GST 7-7 and gamma-L-Glu-L-Cys-L-Asp, which used CDNB but not ETA as acceptor substrate. In general, GST 7-7 was better than GST 8-8 in utilizing these analogues as substrates, and glycyl analogues were better than gamma-glutamyl analogues as both substrates and inhibitors. These results are compared with those obtained earlier with GSH analogues and GST isoenzymes 1-1, 2-2, 3-3 and 4-4 [Adang, Brussee, Meyer, Coles, Ketterer, van der Gen & Mulder (1988) Biochem. J. 255, 721-724] and the implications with respect to the nature of their active sites are discussed. 相似文献
4.
Evidence for an increased rate of choline efflux across erythrocyte membranes in Alzheimer's disease
Butterfield D. Allan Nicholas Maren M. Markesbery William R. 《Neurochemical research》1985,10(7):909-918
Alzheimer's disease (AD), the major dementing disorder of the elderly, is associated with cholinergic neuronal loss and decreased activity of choline acetyl-transferase (CAT). Previous biophysical studies had suggested an altered conformation of membrane proteins in AD erythrocyte ghosts. Since erythrocytes have a choline transport system and cholinergic neurons are implicated in AD, the present experiments were undertaken to determine if the efflux rate of [14C]choline was altered in AD erythrocytes. The mean efflux rate constant was highly significantly increased (P<0.01) by greater than 25% in 9 drug-free AD patients compared to 9 sex-matched, drug-free controls of similar age. These results are discussed in terms of potential molecular mechanisms to account for cholinergic neuronal loss in AD. 相似文献
5.
The Rate Constants of Valinomycin-Mediated Ion Transport through Thin Lipid Membranes 总被引:6,自引:3,他引:3 下载免费PDF全文
Electrical relaxation experiments have been performed with phosphatidylinositol bilayer membranes in the presence of the ion carrier valinomycin. After a sudden change of the voltage a relaxation of the membrane current with a time constant of about 20 μsec is observed. Together with previous stationary conductance data, the relaxation amplitude and the relaxation time are used to evaluate the rate constants of valinomycin-mediated potassium transport across the lipid membrane. It is found that the rate constants of translocation of the free carrier S and the carrier-ion complex MS+ are nearly equal (2·104 sec-1) and are of the same order as the dissociation rate constant of MS+ in the membrane-solution interface (5·104 sec-1). The equilibrium constant of the heterogeneous association reaction M+ (solution) + S (membrane) → MS+ (membrane) is found to be ~ 1 M-1, about 106 times smaller than the association constant in ethanolic solution. 相似文献
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Carbonic anhydrase in the animal kingdom 总被引:1,自引:0,他引:1
T H Maren 《Federation proceedings》1967,26(4):1097-1103
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B. Ketterer 《The Biochemical journal》1965,96(2):372-376
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European Journal of Wildlife Research - Bei 30 Birkhühnern wurde nach kontrolliert durchgeführter Trinkwasservaccination gegen Newcastle Disease (ND) (Erstimpfung mit Hitchner B1,... 相似文献
9.
Stephen Maren 《Molecular neurobiology》1996,13(1):1-22
Numerous studies in both rats and humans indicate the importance of the amygdala in the acquisition and expression of learned
fear. The identification of the amygdala as an essential neural substrate for fear conditioning has permitted neurophysiological
examinations of synaptic processes in the amygdala that may mediate fear conditioning. One candidate cellular mechanism for
fear conditioning is long-term potentiation (LTP), an enduring increase in synaptic transmission induced by high-frequency
stimulation of excitatory afferents. At present, the mechanisms underlying the induction and expression of amygdaloid LTP
are only beginning to be understood, and probably involve both theN-methyl-d-aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) subclasses of glutamate receptors. This article
will examine recent studies of synaptic transmission and plasticity in the amygdala in an effort to understand the relationships
of these processes to aversive learning and memory. 相似文献
10.
Iturin A: A potential new fungicide for stored grains 总被引:6,自引:0,他引:6
The removal of many synthetic fungicides from the market has created a demand for new, environmentally safe fungicides. Iturin A, a cyclic lipopeptide produced byBacillus subtilis, has strong antifungal properties and low mammalian toxicity. To determine the efficacy of this compound as a potential fungicide on stored feed grains, lots of corn, peanuts and cottonseed were treated with varying concentrations of iturin A. The mycoflora of treated seed was assayed along with that of untreated seed and seed treated with fungicides used commercially for planting seed. Fungal species varied considerably in their sensitivity to iturin A. Significant reductions in total mycoflora occurred in most seed lots tested at iturin A concentrations of 50 to 100 ppm. 相似文献