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1.
Interferon induction of polyamine-dependent protein kinase activity in Ehrlich ascites tumor cells 总被引:1,自引:0,他引:1
V Sekar V J Atmar M Krim G D Kuehn 《Biochemical and biophysical research communications》1982,106(2):305-311
Treatment of Ehrlich ascites tumor cell cultures with interferon induces a protein kinase activity that is activated by the polyamines, spermidine and spermine. Putrescine antagonizes the activation. The protein kinase yields a phosphorylated endogenous polypeptide of Mr 68,000–70,000. The polyamine-dependent protein kinase activity cofractionates with a double-stranded RNA-dependent protein kinase activity during affinity chromatography on poly (I) ·poly (C) - agarose or by chromatography on phosphocellulose. The double-stranded RNA-dependent protein kinase also phosphorylates an endogenous polypeptide of Mr 68,000–70,000. Unsuccessful attempts to discriminate between these two protein kinase activities on the bases of their respective capacities to be activated by either double-stranded RNA or spermidine/spermine, suggest that a single protein kinase enzyme may be activated by these strikingly dissimilar modifiers. 相似文献
2.
A.W. Ford-Hutchinson A. Rackham R. Zamboni J. Rokach S. Roy 《Prostaglandins & other lipid mediators》1983,25(1):29-37
Synthetic leukotriene B4 (LTB4) and its ω-oxidation products, 20 OH-LT4 and 20 COOH-LTB4, were tested for their ability to induce the aggregation of rat neutrophils , to contract the guinea pig parenchymal strip and to cause vascular permeability changes in rabbit skin . 20 OH-LTB4 had 10, 100 and 20% of the activity of LTB4 in the neutrophil aggregation, parenchymal strip and vascular permeability assays respectively. 20 C00H-LTB4 was inactive and showed <1% of the activity of LTB4. These results show that while ω-oxidation is a route for biological inactivation of LTB4, 20 OH-LTB4 still retains significant biological activity. 相似文献
3.
P Plevani L Capucci G Badaracco D Breviario N Sacchi G Cattoretti E Ginelli 《Biochemical and biophysical research communications》1982,108(3):1196-1203
The polypeptide structure of terminal transferase purified from human lymphoblasts was examined with an immunoblot procedure using rabbit anti-calf thymus terminal transferase antibodies. Two doublets of bands of Mr 58-56,000 and Mr 44-42,000 are the major immunoreactive polypeptides. Only the Mr 44-42,000 polypeptides can be efficiently renatured after polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. Controlled degradation with trypsin produces fully active enzyme containing the α and β polypeptides typical of the low molecular weight terminal transferase, suggesting that the different forms of purified terminal transferase may arise by proteolysis of the Mr 58,000 polypeptide. 相似文献
4.
A Rosner K M Jakob J Gressel D Sagher 《Biochemical and biophysical research communications》1975,67(1):383-391
A 0.5 × 106r RNA found in plastids of the aquatic angiosperm , is synthesized at a much higher rate than any other rapidly labeling RNA species about h after dark-grown plants are transferred to light. The pulse labeling kinetics of the 0.5 × 106r RNA after transfer to light, argue against its involvement in the biogenesis of plant rRNAs. Although poly(A) RNA is found in , poly(A) sequences are not detected in the 0.5 × 106r RNA; yet a sucrose gradient fraction which includes RNA of this r stimulates amino acid incorporation by an cell free extract more than other RNA fractions. The possible involvement of the 0.5 × 106r RNA as a chloroplast messenger is discussed. 相似文献
5.
C.Channa Reddy Nan-qian Li Chen-Pei D. Tu 《Biochemical and biophysical research communications》1984,121(3):1014-1020
A new glutathione -transferase has been purified to homogeneity from 105,000 × g supernatant of Sprague-Dawley rat liver homogenates. The purified enzyme exhibited specific activities of approximately 1.8, and 0.12 μmoles. min?1. mg?1 toward 1-chloro 2,4-dinitrobenzene and cumene hydroperoxide respectively. The SDS gel electrophoresis data on subunit composition revealed that the new transferase is composed of two subunits with an identical Mr of 24,400 (Yα Family). Our translation experiments with rat liver poly(A) RNAs and substrate specificity data suggest that this subunit is different from the previously reported Ya, Yb and Yc subunits of rat liver glutathione -transferases. Comparatively, the new isozyme showed significant activity toward 1,2 epoxy-3-(P-nitrophenoxy)-propane, ethacrynic acid and P-nitrophenyl acetate, 0.4, 0.34 and 0.18 μ moles. min?1. mg?1 respectively. 相似文献
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7.
M R Walters W Hunziker A W Norman 《Biochemical and biophysical research communications》1981,98(4):990-996
Previous studies have demonstrated that unoccupied 1,25-dihydroxyvitamin D3 receptors are associated with crude chromatin under hypotonic conditions . The data presented herein show that unoccupied 1,25-dihydroxyvitamin D3 receptors appear to be associated with chromatin prior to solubilization by dilution/homogenization in both high and low salt buffers. Additionally the unoccupied receptors are recovered nearly quantitatively from purified nuclei. These results suggest that unoccupied 1,25-dihydroxyitamin D3 receptors may be localized within nuclei . 相似文献
8.
Darwin D. Smith Scott J. Norton 《Biochemical and biophysical research communications》1980,94(4):1458-1462
Sinefungin and A9145C, antifungal antibiotic analogs of S-adeno-sylmethionine isolated from , have been found to be very effective inhibitors of cyclopropane fatty acid synthase from . Both compounds exhibit linear competitive inhibition with a Ki for Sinefungin of 220 nM and a Ki for A9145C of 11 nM. 相似文献
9.
T.K. Gray F.W. Maddux G.E. Lester M.E. Williams 《Biochemical and biophysical research communications》1982,109(3):723-729
Rodent macrophages metabolized 25-hydroxyvitamin D3 to an unidentified metabolite during incubations. The production of this macrophage-derived metabolite of 25-hydroxyvitamin D3 increased as the substrate concentration was raised. A two step high pressure liquid chromatography system revealed a unique elution position of this macrophage-derived metabolite that did not match the elution positions of any of the vitamin D3 metabolites available in this laboratory. This unique metabolite was formed within one minute by incubated macrophages although its formation increased gradually up to 60 minutes of incubation. 相似文献
10.
A particulate factor of rat liver is described which interconverts three forms of rat liver cytosolic tyrosine aminotransferase with no alteration of enzyme activity. The factor appears to be a heat- and pH-sensitive lysosomal protein. The interconversion process is stimulated by 2.5 mM MgCl2 and 2.5 mM ATP. Asparate aminotransferase multiple forms are also susceptible to interconversion by the lysosomal factor. The properties of the factor explain several anomalous effects of manipulation on the tyrosine aminotransferase forms which have been reported in the literature and implicate the form interconversion in the degradation of tyrosine aminotransferase. 相似文献
11.
OKY-1581 is an effective inhibitor of thromboxane synthesis and . The generation of thromboxane B2 (TxB2), prostaglandin E (PGE) and prostaglandin F (PGF) was measured following clotting and during platelet aggregation induced by collagen. The presence of OKY 1581 either or caused a reduction in TxB2 generation during clotting and platelet aggregation with a concomitant increase in PGE and PGF. The effect could be observed two hours after oral or subcutaneous administration of 5 to 100 mg per rabbit and lasted for 24 to 48 hours. The reduction in TxB2 was not accompanied by an inhibition of clotting or platelet aggregation. OKY-1581 appears to be a suitable agent for studying the role of TxB2 in atherosclerosis. 相似文献
12.
C Hedgcoth K Thomas K Scheets S Allen 《Biochemical and biophysical research communications》1980,95(2):880-886
When murine sarcoma virus-transformed cells are labeled with [3H]lysine for various periods, 5 of 6 isoaccepting lysine tRNAs separable by RPC-5 chromatography are aminoacylated in 1 hr to the same extent that they are aminoacylated . The sixth isoacceptor, tRNA6Lys, is not aminoacylated to a measurable extent in 1 hr, although it is present in the tRNA prepared from the cells. All six isoacceptors are aminoacylated with [3H]lysine when the labeling period is 2 or 3 hr. These results further show that correlations of the amount of tRNA4Lys with cell division accurately reflect the situation . Results of differential centrifugation indicate that tRNA6Lys occurs in mitochondria. 相似文献
13.
Release and activation of phosphorylase phosphatase upon rupture of organelles from rat liver 总被引:6,自引:0,他引:6
Liver extracts (8000 × for 10 min) from fasted rats contain about 4 times more phosphorylase phosphatase activity when the liver was homogenized in a hypotonic medium or frozen before homogenization. This increase is caused by: (i) release of partially latent phosphatases (r=60 000 and 45 000 in sucrose gradient centrifugation) from ruptured organelles; (ii) rapid activation of phosphatase in the ruptured pellet by endogenous protease(s) which can be blocked by p-tosyl-L-lysine chloromethyl ketone. Only the r=60 000 enzyme, associated with the nuclei, can be activated proteolytically, with conversion to an r=45 000. 相似文献
14.
A protein containing fraction that will bind 1,25-dihydroxyvitamin D3 both and has been solubilized from the nuclear-debris fraction of rat intestinal mucosa and purified 15-fold. 相似文献
15.
Cytoplasmic free and bound polysomes were isolated from bovine adrenal cortex, and used to program protein synthesis in rat liver cell sap and wheat germ lysate systems. Synthesis of adrenodoxin(Ad) and adrenodoxin reductase(AdR) in the cell-free systems was determined by immunoprecipitation using monospecific antibodies, and the sizes of the products were analyzed by SDS-polyacrylamide gel electrophoresis. Ad was synthesized by both free and bound polysomes as a putative large precursor having molecular weight of approximately 20,000 daltons, which was processed to mature size Ad (MW 12,000 daltons) by incubation with adrenal cortex mitochondria. On the other hand, AdR was synthesized only by free polysomes apparently as the mature size product. 相似文献
16.
A method for demonstrating proestrogens has been developed. The method involves the incubation of the potential proestrogen with liver microsomes and NADPH in the presence of rat uteri, followed by examination of the effects of metabolism of the compound on the distribution of uterine estrogen receptor (R) in the cytosol (Rc) and in the nucleus (Rn). Thus, we examined whether DDT derivatives, which possess estrogenic activity , exhibit pro-estrogenic properties . Using this method, it appears that methoxychlor is a proestrogen, since the presence of microsomal enzymatic activity is required for methoxychlor to elicit translocation of uterine Rc into the nucleus, namely, the lowering of Rc and elevation of Rn. By contrast, o,p'DDT was active in translocating Rc and did not require the presence of microsomal enzymes for activity. 相似文献
17.
Electron spin resonance detection of free radicals in the mercaptan-activation and UV-inactivation of neocarzinostatin 总被引:3,自引:0,他引:3
Differentiation of chick embryo myoblasts requires both cell-cell recognition and cell-cell fusion. Prostaglandin E1 is known to play a role in controlling fusion, and a specific receptor has been postulated. We demonstrate two peaks of specific binding activity for prostaglandin E1 during myoblast differentiation : one at 36 hours and one at 44 hours of culture. The prostaglandin binding activity of both peaks is sensitive to the inhibitors of prostaglandin synthesis, indomethacin and aspirin, and to the antibiotic tunicamycin. The 36 hour peak of binding activity occurs at the same time as the process of cell-cell recognition (24–36 hours) and recognition and prostaglandin binding exhibit similar sensitivity to indomethacin, aspirin and tunicamycin. 相似文献
18.
Effect of prostaglandin E2 on vascular responses of the rabbit kidney to nerve stimulation and noradrenaline, in vitro and in situ 总被引:2,自引:0,他引:2
The effect of prostaglandin E2 on vascular responses of the rabbit kidney to renal nerve stimulation and noradrenaline was examined and as a test of the hypthesis that prostaglandins of the E series may be involved in the regulation of adrenergic neuroeffector transmission. Intraarterial administration of prostaglandin E2 to the kidney caused marked inhibition of vascular responses to nerve stimulation whereas the responses to noradrenaline were not significantly altered. In the preparation, vascular responses to both nerve stimulation and noradrenaline were inhibited by prostaglandin E2 infusion, although its effect on responses to nerve stimulation was approximately twice that observed on responses to noradrenaline.It is concluded that prostaglandin E2 acts primarily at a prejunctional level of adrenergic neuroeffector transmission in the kidney, although a postjunctional effect has also been observed. 相似文献
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The intestinal nuclear receptor for lα,25-dihydroxyvitamin D3 has been utilized to determine the ability of vitamin D-active sterols to compete with this hormone at the molecular level. 25-Hydroxyvitamin D3 and lα-hydroxyvitamin D3 must be present in 150 and 450 times the concentration respectively of lα,25-dihydroxyvitamin D3, , to displace the physiologic hormone. These data indicate that: i) superphysiologic levels of 25-hydroxyvitamin D3 may simulate lα,25-dihydroxyvitamin D3 and act directly on isolated target organs and ii) the biologic potency observed for low doses of lα-hydroxyvitamin D3, , is probably the result of 25-hidroxylation of the lα-derivative to form lα,25-dihydroxyvitamin D3. 相似文献