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We have investigated the protease activity, present in human serum, that digests the serum amyloid A (SAA) protein. SAA radiolabeled with 125I was incubated at 37 degrees C with serum and plasma and analyzed for degradation products by alkaline urea-polyacrylamide gel electrophoresis and gel filtration chromatography. Serum initially digested SAA to intermediates of 3000-5000 in molecular weight, and these were further degraded to smaller peptides with prolonged incubation. SAA was not degraded by plasma anticoagulated with ethylenediaminetetraacetic acid (EDTA) or heparin. Recalcification of plasma anticoagulated with EDTA led to the generation of protease activity against SAA whereas EDTA plasma defibrinated with thrombin was inactive. We employed both nonselective and selective protease inhibitors and synthetic substrates for kallikrein and plasmin to further characterize the serum protease. These studies demonstrated that degradation of SAA is not directly attributable to enzymes involved in coagulation, kinin formation, or fibrinolysis, but the unidentified protease may be activated by one of the clotting factors. The specificity of the SAA degradation was demonstrated in experiments with three of the well-characterized apolipoproteins. Apolipoproteins A-I, C-I, and C-III-1, which also associate with the plasma high-density lipoproteins, were not degraded by serum although they were good substrates for purified thrombin and plasmin. 相似文献
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Antileptospiral activity of serum. I. Normal and immune serum 总被引:10,自引:4,他引:6
Johnson, Russell C. (University of Minnesota, Minneapolis), and Louis H. Muschel. Antileptospiral activity of serum. I. Normal and immune serum. J. Bacteriol. 91:1403-1409. 1966.-Normal serum was found to exert a leptospiricidal effect, mediated by the complement system, against the nonpathogenic leptospires. Although resistant to normal serum, the pathogenic serotypes were susceptible to antiserum plus complement. Several variables in these immune leptospiricidal reactions were investigated. A reaction period of 3 hr at 37 C between serum substances and 1-day-old cells provided a maximal leptospiricidal effect. The normal serum of the rabbit, guinea pig, bovine, and human were leptospiricidal against the nonpathogenic serotypes, and, in conjunction with rabbit antiserum, rabbit and bovine complement were leptospiricidal against the pathogenic serotypes. Studies with C(14)-labeled leptospires indicated that the immune leptospiricidal reaction was associated with a loss of permeability control. Thus, like the gram-negative bacteria, the treponemes, erythrocytes, and nucleated mammalian cells, the leptospires may be included as cell types susceptible to the antibody-complement system. 相似文献
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Summary Putrescine-oxidase activity was found in fetal bovine serum (FBS) with a pH optimum of 8.0 and in adult bovine serum (ABS)
with a pH optimum of 9.8. The crude FBS enzyme had a KM for putrescine of 2.58×10−6
m and a Vmax of 0.53 nmol per hr per 50 μl serum. Aminoguanidine competitively inhibited the enzyme with a KI of 1.8×10−8
m. Spermidine and spermine proved competitive inhibitors of putrescine for both the FBS and the crude ABS putrescine oxidases.
The Vmax for the ABS putrescine oxidase was 2.10 nmol per hr per 50 μl serum, and the KM for putrescine, 50.3×10−6
m. The K1 of the ABS putrescine oxidase for aminoguanidine was 41×10−6
m. On the basis of both the KM and KI values, the adult serum enzyme, at its optimal pH of 9.8, bound spermidine and spermine more avidly than the smaller putrescine
and aminoguanidine; whereas the FBS enzyme, at pH 8.0, bound aminoguanidine and putrescine more tightly than the larger polyamines.
Each of the enzymes retained over 80% of its activity after heating at 56°C for 30 min. Applications of these data to the
study of polyamines in tissue culture and to the purification of diamine oxidases are discussed.
This work was supported in part by a grant from the Cystic Fibrosis Foundation. 相似文献
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Kazuo Nakasuji Kan Usada Takashi Kawasaki Emi Dote Satsuki Hayashi Go Mitsui Kazuya Adachi Michiko Fujihara Yukari Shimbo Koichi Kono 《Biological trace element research》2006,110(2):119-131
Ammonium citratoperoxotitanate IV (TAS-FINE) is a water-soluble titanium complex used to synthesize a photocatalytic titanium(IV)
oxide film. This study was aimed to investigate the LD50, dose-response, time-course response, and renal toxicity of TAS-FINE using an animal model. Serum titanium (S-Ti) and its
24-h urinary excretion (U-Ti) were determined by inductively coupled plasma-argon emission spectrometry (ICP-AES) after a
single oral TAS-FINE administration to male Wistar rats. The LD50 of TAS-FINE was 7.97 g/kg body weight in 24 h, and its half-life was 3.78±1.28 d for S-Ti and 2.19±0.09 d for U-Ti. Although
TAS-FINE was not easily absorbed in the gastrointestinal tract, it was distributed into the bloodstream in a dose-dependent
manner. Within 24 h, 0.189% of administrated Ti was excreted via urine. It was speculated that TAS-FINE formed conjugates
with serum constituents that resulted in nephrotoxicity resulting from an allergic reaction. The observed indices in this
study were revealed to be good indicators for TAS-FINE exposure. The analytical method and animal model described in this
study will help to further elucidate details about human exposure to TAS-FINE, which in recent times has become an occupational
and environmental toxicant of concern. 相似文献
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A radioimmunoassay (RIA) for measurement of serum haloperidol is described. Compared to gaschromatography (GC), RIA values average 40% higher. However, a simple organic extraction of serum yields statistically equivalent RIA and GC haloperidol determinations. For both men and women combined, there was a positive correlation between dose (mg/kg/day) and steady-state serum haloperidol level (r = +0.86) and between steady-state serum haloperidol and serum prolactin (PRL) concentration (r = +0.87). 相似文献
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Malcolm C Bateson 《BMJ (Clinical research ed.)》1978,1(6114):718-719
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Putrescine-oxidase activity was found in fetal bovine serum (FBS) with a pH optimum of 8.0 and in adult bovine serum (ABS) with a pH optimum of 9.8. The crude FBS enzyme had a KM for putrescine of 2.58 x 10(-6) M and a Vmax of 0.53 nmol per hr per 50 microliter serum. Aminoguanidine competitively inhibited the enzyme with a KI of 1.8 x 10(-8) M. Spermidine and spermine proved competitive inhibitors of putrescine for both the FBS and the crude ABS putrescine oxidases. The Vmax for the ABS putrescine oxidase was 2.10 nmol per hr per 50 microliter serum, and the KM for putrescine, 50.3 x 10(-6) M. The K1 of the ABS putrescine oxidase for aminoguanidine was 41 x 10(-6) M. On the basis of both the KM and KI values, the adult serum enzyme, at its optimal pH of 9.8, bound spermidine and spermine more avidly than the smaller putrescine and aminoguanidine; whereas the FBS enzyme, at pH 8.0, bound aminoguanidine and putrescine more tightly than the larger polyamines. Each of the enzymes retained over 80% of its activity after heating at 56 degrees C for 30 min. Applications of these data to the study of polyamines in tissue culture and to the purification of diamine oxidases are discussed. 相似文献
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