共查询到20条相似文献,搜索用时 31 毫秒
1.
J P Aymard C Janot J C Chermann M E Briquel P Perrier P Alexandre F Streiff 《Revue fran?aise de transfusion et immuno-hématologie》1985,28(3):261-265
49 french haemophiliacs (haemophilia A: 41 patients; haemophilia B: 8 patients) were serologicaly tested for LAV antibodies: 10 patients (20.4%) were seropositive including 9 (21.9%) with haemophilia A and 1 (12,5%) with haemophilia B. Between seronegative and seropositive patients total lymphocyte and T-lymphocyte sub-populations counts were not significantly different. The mean serum IgG level was higher and palpable lymphadenopathy more frequently encountered among seropositive patients. 相似文献
2.
F H Herrmann M Wehnert W Schr?der 《Folia haematologica (Leipzig, Germany : 1928)》1990,117(4):601-607
Since 1986 the genomic diagnosis of haemophilia A and B in the GDR is realized as a national programme. Until Aug. 1989 56 families at risk of haemophilia A are analysed using RFLPs of different intragenic and intergenic probes (BclI/F8e 16-19, KpnI-XbaI/int 22, TaqI/St 14.1). 117 out of 162 females at risk being heterozygous were identified as carriers, in 40 cases the carrier state was excluded, and in 5 females the data were not informative. Prenatal diagnosis was offered to 93 carriers in reproductive age. Six genomic prenatal diagnoses in haemophilia A were performed. In four patients different partial deletions of factor VIII:C gene were found. 10 families of haemophilia B were analysed using intragenic and intergenic probes (P 1; pX58dIIIc). 14 females were identified as carriers, 11 were excluded. The application of direct and indirect gene diagnosis in haemophilia is discussed. 相似文献
3.
The incidence and distribution of CpG----TpG transitions in the coagulation factor IX gene. A fresh look at CpG mutational hotspots. 总被引:16,自引:4,他引:12
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P M Green A J Montandon D R Bentley R Ljung I M Nilsson F Giannelli 《Nucleic acids research》1990,18(11):3227-3231
The mutations of 76 haemophilia B patients representing the whole population registered with the Malm? haemophilia centre (42) and referrals from the UK, were characterised. RFLP haplotype analysis of the defective genes indicated that 51 single base pair substitutions were definitely of independent origin and 27 of these were CpG----TpG or CpA transitions. This represents a 38-fold excess over other single-base changes. Most of such transitions (82%) occur at 9 CpG sites occupying critical positions (transitions at 3 sites substitute essential arginines, while at 6 sites transition to TpG creates stop codons). Sixteen of the 18 possible transitions at these 9 sites cause clear haemophilia B and should be fully ascertained in our haemophilia B population. This allowed the direct estimate of the rate of CpG transitions. This is 1.05 x 10(-7) substitutions per base per gamete per generation. The marked excess of CpG transitions in haemophilia B appears partly due to the high proportion of CpG sites at critical positions (at least 9 out of 20). We propose that this follows from the fact that male hemizygosity makes X-linked genes particularly susceptible to selective forces that tend to fix CpG sites arising at critical positions. 相似文献
4.
smg p21B/rap1B p21, a member of ras p21-like small GTP-binding protein superfamily, has been shown to be phosphorylated by cyclic AMP-dependent protein kinase (protein kinase A). We show here that this protein was also phosphorylated by cyclic GMP-dependent protein kinase (protein kinase G) in a cell-free system. The same serine residue (Ser179) in the C-terminal region was phosphorylated by both protein kinases G and A. The Km and Vmax values of smg p21B for protein kinase G were 5 x 10(-7) M and 4 x 10(-9) mol/min/mg, and those values for protein kinase A were 1 x 10(-7) M and 3 x 10(-8) mol/min/mg. 相似文献
5.
C. A. Sabin K. J. Pasi A. N. Phillips P. Lilley M. Bofill C. A. Lee 《BMJ (Clinical research ed.)》1996,312(7025):207-210
OBJECTIVE--To investigate the hypothesis that high usage of clotting factor concentrate, rather than HIV infection, is the cause of immunodeficiency and AIDS in men with haemophilia. DESIGN--A comparison of AIDS defining conditions and CD4 counts in HIV positive and HIV negative patients with haemophilia matched for usage of clotting factor concentrate. SETTING--A comprehensive care haemophilia centre. SUBJECTS--17 HIV positive and 17 HIV negative male patients with haemophilia A (age range 12-60 at beginning of study period) who had received similar amounts of clotting factor concentrate yearly over the years 1980-90. MAIN OUTCOME MEASURES--Clinical events listed as AIDS defining in the Centers for Disease Control AIDS definition; CD4 lymphocyte counts; death. RESULTS--Of 108 HIV positive male patients with haemophilia A, only 17 could be matched to an HIV negative patient. This was due to the much higher average usage of factor VIII in the HIV positive group. Between 1980 and 1990, 16 clinical events occurred in nine of the 17 HIV positive patients. No event occurred in the 17 HIV negative patients. In each pair the mean CD4 count during follow up was, on average, 0.5 x 10(9)/l lower in the HIV positive patient. CONCLUSION--These data reject the hypothesis that high usage of clotting factor concentrate, rather than HIV infection, is the cause of immunodeficiency and AIDS in men with haemophilia. 相似文献
6.
A Girolami R Dal Bo Zanon M Procidano 《Folia haematologica (Leipzig, Germany : 1928)》1981,108(6):863-871
In investigations made in 32 patients with haemophilia A and 28 patients with haemophilia B the possibility of utilizing the trypsin clotting time (K-test) was tested in diagnosing both diseases. 23 plasmas of healthy test persons were used as controls and revealed a mean value of the K-test amounting to 24.52 +/- 0.75 seconds. With a mean value amounting to 30.025 +/- 2.88 seconds the K-test was clearly and from a statistical point of view significantly prolonged in hemophilia B contrary to hemophilia A with a slight prolongation amounting to 26.95 +/- 2.03 seconds. Possible causes for the response of the trypsin clotting tie are discussed. 相似文献
7.
Sakakura Y Nakagawa Y Ohzeki T 《The Journal of steroid biochemistry and molecular biology》2006,99(2-3):115-120
Dehydroepiandrosterone (DHEA) is the predominant steroid hormone secreted by adrenal gland, and it has been proposed in recent years that DHEA has significant effects on immune function. We investigated the effect of DHEA (1 x 10(-5) - 1 x 10(-8)M) on proliferation of human T cells and B cells and on immunoglobulin production, a representative function of B cells. High doses of DHEA (1 x 10(-5)) significantly inhibited proliferation of peripheral blood mononuclear cells (PBMCs) and T cells induced by T cell mitogens hemagglutinin (PHA) and concanavalin A (Con A). Proliferation of PBMCs induced by B cell mitogens pokeweed mitogen (PWM) was increased by 1 x 10(-7) - 1 x 10(-6)M DHEA. Proliferation of PBMCs and B cells induced by Staphylococcus aureus Cowan strain I (SAC) was not significantly changed at any concentrations of DHEA. However, a concentration of 1 x 10(-7)M DHEA tended to potentiate their proliferation. This study suggested that DHEA acted on T and B lymphocytes differentially in immune system. 相似文献
8.
The prevalence of serological markers for present and past hepatitis B virus (HBV) infection and antibodies against cytomegalovirus (CMV) among Norwegians with coagulation factor defects was examined in serum samples collected before virus-inactivated coagulation concentrates came into use. Sera collected in 1985/86 from 324 of 377 (86%) registered persons with such defects were available. Three persons were chronic carriers of HBsAg. The prevalence of HBV antibodies was 28% compared with about 5% in the general population. The highest prevalence rate was found among patients with severe haemophilia A (44%) and in patients with haemophilia B (39%). The prevalence of anti-CMV antibodies was 75% which is similar to that found in the general Norwegian population. 相似文献
9.
The influence of extracellular hydrogen on the metabolism of Bacteroides ruminicola, Anaerovibrio lipolytica and Selenomonas ruminantium 总被引:3,自引:0,他引:3
C Henderson 《Journal of general microbiology》1980,119(2):485-491
Strains of three anaerobic rumen bacteria, Bacteroides ruminicola, Anaerovibrio lipolytica and Selenomonas ruminantium, were able to use extracellular H2 to reduce fumarate to succinate. Each bacterium possessed membrane-bound hydrogenase and fumarate reductase activity. Membrane-bound cytochrome b was reducible by H2 and oxidizable by fumarate in each bacterium. The apparent Km values for hydrogen of the hydrogenases were 4 . 5 x 10(-6) M, 1 . 4 x 10(-5) M and 4 . 4 x 10(-5) M for B. ruminicola, A. lipolytica and S. ruminantium, respectively. The apparent Km values for fumarate of the fumarate reductases were approximately 1 . 0 x 10(-4) M for each bacterium. 相似文献
10.
Ansari HR Nadeem A Talukder MA Sakhalkar S Mustafa SJ 《American journal of physiology. Heart and circulatory physiology》2007,292(1):H719-H725
We have investigated the role of adenosine and its analogs on vasorelaxation of mouse aorta in intact endothelium with rank order of potency as follows: 5'-N-ethylcarboxamidoadenosine (NECA) > 2-chloroadenosine > adenosine > CGS-21680, which is consistent with the profile of A(2B)-adenosine receptor (A(2B)AR). In endothelium-intact tissues, acetylcholine produced relaxation ranging from 65 to 80% in phenylephrine (PE, 10(-7) M)-precontracted mouse aorta, whereas no relaxation was observed in endothelium-denuded tissues. The A(2B)AR antagonist alloxazine (10(-5) M) shifted concentration-response curve for NECA (EC(50) = 0.005 x 10(-5) M) to the right with an EC(50) of 2.8 x 10(-5) M, demonstrating that this relaxation is partially dependent on functional endothelium mediated predominantly via A(2B)AR in this tissue. This conclusion was further supported by the following findings: 1) in the endothelium-intact mouse aorta, the EC(50) values for NECA and adenosine were found to be 0.05 and 1.99 x 10(-4) M, respectively; however, in denuded endothelium, these values were 0.098 and 3.55 x 10(-4) M, respectively; 2) NECA-induced relaxation was significantly blocked by N(G)-nitro-l-arginine methyl ester (l-NAME; 10(-4) M) in endothelium-intact tissues, which was reversed by pretreatment with l-arginine (10(-4) M), whereas no significant inhibition was found in endothelium-denuded tissues; 3) total nitrites and nitrates (NOx) in intact endothelium with l-NAME (10(-4) M) alone and in combination with l-arginine were 59% (P < 0.05) and 96%, respectively, in comparison with control (PE + NECA); and 4) endothelial nitric oxide synthase gene expression was found to be 67% (P < 0.05) less in endothelium-denuded as opposed to endothelium-intact mouse aorta. Thus these data demonstrate that adenosine-mediated vasorelaxation is partially dependent on A(2B)AR in mouse aorta. 相似文献
11.
The susceptibility of Agrilus planipennis Fairmaire (Coleoptera: Buprestidae) to selected strains of the entomopathogenic fungi Beauveria bassiana (Balsamo) Vuillemin and Metarhizium anisopliae (Metschnikoff) Sorokin was evaluated through bioassays with direct immersion or foliar exposure under laboratory conditions. Results showed that A. planipennis adults were susceptible to B. bassiana and M. anisoplae. Significant time-mortality response was found for each isolates. Isolate B. bassiana GHA killed A. planipennis adults at a faster rate compared with other isolates tested, with the lowest average time-to-death values. The LC50 values estimated under direct immersion method ranged from 1.7 x 10(5) to 1.9 x 10(7), 3.5 x 10(4) to 5.3 x 10(5), and 4.1 x 10(3) to 2.9 x 10(5) conidia/ml for B. basissiana and from 3.2 x 10(6) to 1.1 x 10(7), 4.5 x 10(3) to 4.5 x 10(5), and 1.4 x 10(2) to 1.2 x 10(5) conidia/ml for M. anisopliae at 4, 5, and 6 d after treatment, respectively. By days 5 and 6, B. bassiana GHA outperformed all other isolates tested except ARSEF 7234, followed by ARSEF 7152, 6393, and 7180. Significant concentration-mortality response was also observed for two B. bassiana GHA formulations, BotaniGard ES and Mycotrol O, and M. anisopliae F52 when insects were treated through foliar exposure. The LC50 values ranged from 114.5 to 309.6, 18.4 to 797.3, and 345.3 to 362.0 conidia/cm2 for BotaniGard, Mycotrol, and M. anisopliae F52, respectively. Based on the results of these bioassays, the efficacy of both B. bassiana GHA formulations and M. anisopliae F52 were similar against adult A. planipennis. The potential use of entomopathogenic fungi for management of A. planipennis in North America is discussed. 相似文献
12.
Peritoneal macrophages (PM) were obtained by peritoneal dialysis from a regularly menstruating woman with renal failure. Macrophages (10(6) cells) were incubated at 37 degrees C for various periods of time (0-4 hr) in the presence of 14C-androstenedione or 3H-androstenedione and various concentrations (0.06-5.06 microM) of nonradiolabeled androstenedione (A). Testosterone (T) formed was purified by column chromatography, thin layer chromatography, acetylation, and recrystalization to constant 3H:14C ratios. The rate of formation of T from A was linear for nearly 2 hr. Conversion of A to T was linear at cell numbers in the incubation up to 1 x 10(6). The formation of T from A followed Michaelis-Menten kinetics at concentrations of A between 0.06 and 5.06 microM. The apparent Km of the enzyme for A was 0.75 microM and the Vmax for T formation from A in these cells was 33.9 pmol x hr-1 x 10(6) cells-1. PM were obtained also from normal patients (n = 6) and patients with endometriosis (n = 5). The rate of T synthesis from A in PM obtained from patients with endometriosis [527 +/- 263 pmol x hr-1 x 10(6) cells-1 (mean +/- SEM, n = 5)] was similar to that observed in PM obtained from normal patients [518 +/- 226 pmol x hr-1 x 10(6) cells-1 (mean +/- SEM, n = 6)]. We observed a near 30-fold variation in the rate of formation of T from A by PM obtained from different individuals (range 54 to 1580 pmol x hr-1 x 10(6) cells-1). Further study is needed to elucidate the physiologic significance of PM androgen metabolism and its relationship to reproductive function. 相似文献
13.
Dobbins DE 《Mediators of inflammation》1992,1(4):241-246
Neurokinin A and B are putative inflammatory mediators. We assessed their ability to alter prenodal lymphatic resistance. Intralymphatic neurokinin A (3.0 x 10(-6), 3.0 x 10(-5) and 3.0 x 10(-4) mol l(-1)) significantly constricted lymphatics at the two highest doses. Preliminary experiments suggested that neurokinin B might dilate lymphatics. To test this, lymphatic pressure was increased by norepinephrine (3.1 x 10(-6) mol l(-1)). Neurokinin B (2.7 x 10(-4) mol l(-1)) was then infused intralymphatically during norepinephrine infusion. Norepinephrine increased perfusion pressure from 5.6 +/- 0.6 mmHg to 12.1 +/- 1.4 mmHg. Subsequent infusion of neurokinin B significantly decreased lymphatic perfusion pressure from 11.9 +/- 1.3 mmHg to 9.9 +/- 1.1 mmHg. These data indicate that neurokinin A and B can alter lymphatic resistance and are consistent with the hypothesis that lymph vessel function may be subject to modulation by neurokinins. 相似文献
14.
Determination of thalidomide in transport buffer for Caco-2 cell monolayers by high-performance liquid chromatography with ultraviolet detection 总被引:2,自引:0,他引:2
Zhou S Li Y Kestell P Paxton JW 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2003,785(1):165-173
We report simple validated HPLC methods for the determination of thalidomide in the transport buffer for the human colonic cell line (Caco-2) cell monolayers. An aliquot of 50 microl of the mixture was injected onto a Spherex C(18) column (150 x 4.6 mm; 5 microm) at a flow-rate of 0.5 ml/min of mobile phase consisting of acetonitrile-10 mM ammonium acetate buffer (24:76, v/v, pH 5.5), and thalidomide was detected by ultraviolet detector at a wavelength of 220 nm. Calibration curves for thalidomide were constructed at the concentration range of 0.025-1.0 and 1.0-50 microM in transport buffer. The validated methods were used to determine the transport of thalidomide by Caco-2 monolayers. The transport across the monolayers from the apical (A) to basolateral (B) side was similar to that from B to A side. The apparent permeability coefficient (P(app)) values of thalidomide at 10-300 microM from the A to B and from B to A side was 2-6 x 10(-5) cm/s, with a marked decrease in P(app) values from A to B side at increased thalidomide concentration. The A to B transport appears to be dependent on temperature and sodium ion. Sodium azide, 2,4-dinitrophenol (both ATP inhibitors), 5-fluorouracil, cytidine and glutamic acid significantly inhibited the transport of thalidomide. These results indicate that the transport of thalidomide by Caco-2 monolayers was rapid, which might involve an energy-dependent mechanism. 相似文献
15.
D Ferbus S Khosravi J Dumont C Billard 《Journal of biological regulators and homeostatic agents》1990,4(4):127-134
We investigated the correlations between the in vivo-in vitro induction of 2'-5' oligoadenylate synthetase (2-5A synthetase) by IFN-alpha in cells isolated from patients with low-grade nodular non-Hodgkin's lymphoma (NHL) and subsequent clinical responses of these patients to IFN-alpha therapy. Eleven patients were treated daily with 9 x 10(6) U of IFN-alpha 2a in a phase II trial. After an eight week treatment, four patients achieved complete remission, one a partial response, one a minor response, and five failed to respond. Basal levels of 2-5A synthetase in lymph node tumor B cells and peripheral blood mononuclear cells (PBMC) isolated before therapy differed from patient to patient and were significantly lower than in PBMC from healthy donors (P less than 0.03). In vivo single injections of 9 x 10(6) U IFN-alpha 2a induced the 2-5A synthetase in PBMC from all patients to various degrees without quantitative relation to the clinical responses. Injection of a tenfold lower dose resulted in effects of similar extent in most cases. In vitro, IFN-alpha 2a induced the 2-5A synthetase in lymph node tumor B cells isolated before therapy, and the degree of induction was significantly higher in patients who proved to respond to therapy than in patients who displayed no or minor responses (P less than 0.013). This indicates that, in nodular NHL, the 2-5A synthetase assay may have some predictive value for responsiveness to IFN-alpha therapy. 相似文献
16.
Iu V Burov T D Ba?manov L V Tat'ianenko N M Sokolova I M Tereshchenkova 《Biulleten' eksperimental'no? biologii i meditsiny》1992,113(2):149-150
In vitro comparative studies of effects of amiridin (9-amino-2, 3, 5, 6, 7, 8-hexahydro-1H-cyclopentane (b) choline monohydrate hydrochloride) and tacrine physostigmine and piracetam on monoamine oxidase A (MAO-A) and B (MAO-B) activity in the rat brain were carried out. Piracetam (1 x 10(-4)-1 x 10(-3) M) dose-dependently increased MAO-A and MAO-B activity. At all concentrations used (1 x 10(-7)-5 x 10(-4) M) physostigmine had no effect on MAO-A and MAO-B activity. Amiridin was found to inhibit MAO-B activity at 5 x 10(-4) M concentration only. Tacrine inhibited MAO-A activity at 5 x 10(-4) M concentration. The therapeutical effects of amiridin and tacrine in treatment of Alzheimer disease were not related to their action on MAO-A and -B activity. 相似文献
17.
Three guinea pig testicular, low-molecular-weight, acid-stable inhibitors specific for trypsin-like proteinases were isolated, purified, and characterized. The procedure comprised acid extraction of testicular acetone powder, pH precipitation of the extract, gel filtration of the supernatant on Sephadex G-100 and G-50, ion-exchange chromatography on SP-Sephadex, followed by QAE-Sephadex. Final purification was by rechromatography on Sephadex G-50 superfine gel. The three proteinase inhibitors were labeled A, B, and Cnb, the latter to denote nonbinding of Cnb to the QAE-Sephadex. Components A and Cnb showed competitive, whereas B showed noncompetitive, inhibition against trypsin. All three inhibitors were active against trypsin but were ineffective against chymotrypsin. The inhibition constants, Ki, were obtained using trypsin-catalyzed hydrolysis of the N-benzyloxycarbonyl-L-arginyl amide of 7-amino-4-trifluoro-methylcoumarin (CBZ-Arg-AFC) at pH 8.0. The values were calculated to be, for A, 1.5 x 10(-8) M; for B, 1.5 x 10(-8) M; and, for Cnb, 2.2 x 10(-7) M. The Ki values calculated from inhibition of trypsin-catalyzed hydrolysis of the active site titrant 4-methylumbelliferyl-p-guanidinobenzoate (MUGB) using Easson-Stedman plots were, for A, 7.7 x 10(-9) M; for B, 6.7 x 10(-9) M; and, for Cnb, 1.4 x 10(-7) M. The Mrs as determined by active site titration with MUGB were A, 11.2 kDa; B, 10.5 kDa; Cnb, 17.0 kDa. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis gave Mr values for A of 11 kDa, for B of 4 kDa, and for Cnb of 19 kDa. The discrepancy in Mr values for B indicates that it may function as a dimer or trimer in the active state. 相似文献
18.
A. J. Montandon P. M. Green D. R. Bentley R. Ljung S. Kling I. M. Nilsson F. Giannelli 《Human genetics》1992,89(3):319-322
Summary Mutation rates for X-linked recessive diseases have so far been estimated indirectly by postulating an equilibrium between the loss of defective genes caused by the low reproductive fitness of affected males and the gain resulting from new mutations. Here, for the first time, we directly estimate both the overall and sex-specific mutation rates for haemophilia B by detecting the gene defect of the families registered at the Malmö Haemophilia Centre. These represent a complete sample of the Swedish haemophilia B population (45 out of 77 pedigrees) and contain 23 families with a single affected male. Fifteen of these males had mothers available for study, and of these mothers, 13 had parents available for study. We show that 3 of the above patients and 10 of their mothers carry new mutations, and by extrapolation calculate that 8 males and 98 females should carry new haemophilia B mutations in the Swedish population (8.52 × 106 individuals). This leads to the following estimate of the mutation rates: overall = 4.1 × 10-6; male specific v = 2.1 × 10-5; and female specific u = 1.9 × 10-6. The ratio of such male to female specific mutation rates is thus v/u = 11. 相似文献
19.
The combination in one molecule of functional groups that can interact specifically with different substrate binding areas at the active site of carboxypeptidases A and B has led to the development of potent and specific inhibitors of these enzymes. 2-Benzyl-3-mercaptopropanoic acid (SQ 14,603) has a Ki of 1.1 x 10(-8) M vs. carboxypeptidase A and a Ki of 1.6 x 10(-4) M vs. the B enzyme. 2-Mercaptomethyl-5-guanidinopentanoic acid (SQ 24,798) has a Ki of 4 x 10(-10) M vs. carboxypeptidase B and a Ki of 1.2 x 10(-5) M vs. carboxypeptidase A. It is proposed that the sulfhydryl groups of these inhibitors bind to the catalytically important zinc ions of these enzymes, and that, in conjunction with the benzyl and guanidinopropyl side chains, they are responsible for their specificity. 相似文献
20.
Properties of D-arabinose isomerase purified from two strains of Escherichia coli 总被引:3,自引:3,他引:0
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d-Arabinose isomerase (EC 5.3.1.3) has been isolated from l-fucose-induced cultures of Escherichia coli K-12 and d-arabinose-induced cultures of E. coli B/r. Both enzymes were homogeneous in an ultracentrifuge and migrated as single bands upon disc electrophoresis in acrylamide gels. The s(20,w) was 14.5 x 10(-13) sec for the E. coli K-12 enzyme and 14.3 x 10(-13) sec for the E. coli B/r enzyme. The molecular weight, determined by high-speed sedimentation equilibrium, was 3.55 +/- 0.06 x 10(5) for the E. coli K-12 enzyme and 3.42 +/- 0.04 x 10(5) for the enzyme isolated from E. coli B/r. Both enzyme preparations were active wth l-fucose or d-arabinose as substrates and showed no activity on any of the other aldopentoses or aldohexoses tested. With the E. coli K-12 enzyme, the K(m) was 2.8 x 10(-1)m for d-arabinose and 4.5 x 10(-2)m for l-fucose; with the E. coli B/r enzyme, the K(m) was 1.7 x 10(-1)m for d-arabinose and 4.2 x 10(-2)m for l-fucose. Both enzymes were inhibited by several of the polyalcohols tested, ribitol, l-arabitol, and dulcitol being the strongest. Both enzymes exhibited a broad plateau of optimal catalytic activity in the alkaline range. Both enzymes were stimulated by the presence of Mn(2+) or Co(2+) ions, but were strongly inhibited by the presence of Cd(2+) ions. Both enzymes were precipitated by antisera prepared against either enzyme preparation. The amino acid composition for both proteins has been determined; a striking similarity has been detected. Both enzymes could be dissociated, by protonation at pH 2 or by dialysis against buffer containing 8 m urea, into subunits that were homogeneous in an ultracentrifuge and migrated as single bands on disc electrophoresis in acrylamide gels containing urea. The molecular weight of the subunit, determined by high-speed sedimentation equilibrium, was 9.09 +/- 0.2 x 10(4) for the enzyme from E. coli K-12 and 8.46 +/- 0.1 x 10(4) for the enzyme from E. coli B/r. On the basis of biophysical studies, both isomerases appear to be oligomeric proteins consisting of four identical subunits. 相似文献