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51.
Harry Brumberger Jeffrey L. Lipton Gary Dorfman Eileen Nakano 《The Biochemical journal》1974,143(2):495-496
Small-angle X-ray scattering measurements on native pig thyroglobulin in phosphate buffer, pH6.9, yield a radius of gyration of 6.4nm (64Å), a particle volume of approx. 1.5×103nm3 (1.5×106Å3), an axial ratio of 2.2:1 (assuming an ellipsoidal shape), and a solvation of 0.63g of solvent/g of protein. 相似文献
52.
The isolated rat diaphragm was used to study the effects of 17β-estradiol on basal and insulin-mediated glucose uptake. Rats were injected with estradiol for 2 wk in daily doses of 10 μg/100 g of body weight and were compared to untreated control animals. Estrogen treatment resulted in a 16% decrease in basal glucose uptake by diaphragm muscle as compared to controls. In contrast, in the presence of insulin, glucose uptake by muscle increased 103% above basal in estradiol-treated animals as compared to a 38% rise in the control group. The absolute rate of glucose uptake induced by insulin in the estradiol treated animals (5.8 mg/g/hr) was 22% higher than in controls. These findings were not accompanied by changes in weight gain, plasma glucose and plasma immunoreactive insulin concentrations in the treated animals. In vitro incubation of diaphragm muscle with estradiol did not have an effect on basal or insulin-mediated glucose uptake. 相似文献
53.
The folding of randomly coiled poly(L -glutamic acid) to the helical state has been studied in N-methylacetamide by titration methods. Since this solvent would be expected to form amide-peptide group hydrogen bonds with the unfolded form of the polymer, to a first approximation no helix stabilization could come from intrapolymer hydrogen bonds. The titration data, collected from 30 to 70°C yield the following values per residue for the thermodynamic parameters governing the coil-helix reaction for the uncharged polymer: ΔG30°C°, ?1. 9 ± 0.1 kcal; Δ H°, 0 ± 0.1 kcal; ΔS30°C°, 6.3 ± 0.6 eu. In N-methyl acetamide, the helix is an order of magnitude more stable than in water, and this stabilization appears to be entirely the result of the entropy gained by solvent molecules which are released from the polymer upon folding. 相似文献
54.
Exposures to short periods of high temperature (40 to 50 C) in each 24-hr diurnal temperature cycle (average temperature ca. 25 C) reduced growth of Aspergillus parasiticus and production and accumulation of the aflatoxins when compared with cultures held continuously at 25 C. In contrast, diurnal cycles with an average temperature of ca. 25 C but with minima as low as 10 C did not appreciably affect either growth or toxin production. The ratio of production of aflatoxin B to aflatoxin G increased as the maximal temperature was raised but remained essentially unchanged with decreasing minimal temperatures. 相似文献
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