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1.
Sotaro Yamasaki Mitsuo Shoji Megumi Kayanuma Vladimir Sladek Daniel Ken Inaoka Yuichi Matsuo Tomoo Shiba Luke Young Anthony L. Moore Kiyoshi Kita Yasuteru Shigeta 《BBA》2021,1862(4):148356
Alternative oxidase (AOX) catalyzes the four-electron reduction of dioxygen to water as an additional terminal oxidase, and the catalytic reaction is critical for the parasite to survive in its bloodstream form. Recently, the X-ray crystal structure of trypanosome alternative oxidase (TAO) complexed with ferulenol was reported and the molecular structure of the non-heme diiron center was determined. The binding of O2 was a unique side-on type compared to other iron proteins. In order to characterize the O2 binding state of TAO, the O2 binding states were searched at a quantum mechanics/molecular mechanics (QM/MM) theoretical level in the present study. We found that the most stable O2 binding state is the end-on type, and the binding states of the side-on type are higher in energy. Based on the binding energies and electronic structure analyses, O2 binds very weakly to the TAO iron center (ΔE =6.7 kcal mol?1) in the electronic state of Fe(II)…OO, not in the suggested charge transferred state such as the superoxide state (Fe(III)OO· –) as seen in hemerythrin. Coordination of other ligands such as water, Cl?, CN?, CO, N3? and H2O2 was also examined, and H2O2 was found to bind most strongly to the Fe(II) site by ΔE = 14.0 kcal mol?1. This was confirmed experimentally through the measurement of ubiquinol oxidase activity of TAO and Cryptosporidium parvum AOX which was found to be inhibited by H2O2 in a dose-dependent and reversible manner. 相似文献
2.
Dr. Erik Dybing Jon E. Dahl Frederick A. Beland Snorri S. Thorgeirsson 《Cell biology and toxicology》1986,2(3):341-355
The metabolism and activation of 1-nitropyrene (1-NP) to reactive intermediates by lung microsomes and isolated lung cells was studied. Mutagenicity of 1-NP metabolites was assayed in Salmonella typhimurium TA98NR, a strain lacking a major component of nitroreductase activity. In the presence of NADPH, microsomes from rabbit, rat and hamster lung metabolized 1-NP to mutagenic products to a similar degree. Pretreatment with a mixture of polychlorinated biphenyls (PCB) decreased the formation of mutagenic metabolites by rabbit lung microsomes, but did not affect the production of mutagens by rat or hamster lung microsomes. 3H-1-NP was metabolized to covalently bound protein products at a rate of 82 and 10 pmol/mg by rabbit and hamster lung microsomes, respectively, whereas no binding was detected in rat lung microsomes. PCB-pretreatment increased covalent protein binding of 3 H-1-NP in lung microsomes from hamster and rat, but decreased the binding in rabbit lung microsomes. High performance liquid chromatography analysis indicated that 3H-1-NP was readily converted to ring-hydroxylated products by rabbit and hamster lung microsomes; the rate was much lower with rat lung microsomes. 3H-1-NP was activated to metabolites that covalently bound to protein in isolated rabbit lung cells, with the following rates being observed: Clara cells > lung digest > type II cells. In contrast, covalent protein binding in cells isolated from rat lung was very low. 1-NP was not activated to products mutagenic for S. typhimurium TA 98 N R when co-incubated with cells isolated either from rabbit or rat lung.Abbreviations 1-AP
1-aminopyrene
- DMSO
dimethyl sulfoxide
- EGTA
ethylene glycol-bis(ß-aminoethyl ether)
- EM
electron microscopy
- HEPES
N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid
- HPBS
HEPES-phosphate-buffered-saline
- HPLC
high performance liquid chromatography
- NBT
nitroblue tetrazolium
- 1-NP
1-nitropyrene
- 1-NP-4,5-diol
trans-4,5-dihydro-4,5-dihydroxy-1-nitropyrene
- 1-NP-9,10-diol
trans-9,10-dihydro-9,10-dihydroxy-1-nitropyrene
- 1-NP-4,5-oxide
1-nitropyrene-4,5-oxide
- 1-NP-9,10-oxide
1-nitropyrene-9,10-oxide
- 3-OH-1-NP
3-hydroxy-1-nitropyrene
- 6-/8-OH-1-NP
a mixture of 6- and 8-hydroxy-1-nitropyrene
- PBS
phosphate-buffered saline
- PCB
a mixture of polychlorinated biphenyls (Aroclor 1254)
- TLC
thin layer chromatography 相似文献
3.
《Journal of Free Radicals in Biology & Medicine》1986,2(5-6):393-396
Equilibrium dialysis studies on competitive binding of 59FeCl3 to xanthine oxidase and citrate or ATP have been carried out. Iron binding to the enzyme was observed in the presence of 0.1 mM of either chelator, suggesting that xanthine oxidase is likely to have iron bound in many in vitro experimental systems and raising the possibility that it may be able to compete for intracellular chelatable iron. One high-affinity-binding site per monomer was found, with an affinity constant of 5 × 1012 M−1. The significance of this iron as a Fenton reaction catalyst is discussed. 相似文献
4.
Michael A. Heitkamp James P. Freeman Dwight W. Miller Carl E. Cerniglia 《Archives of microbiology》1991,156(3):223-230
The metabolism of 14C-labeled 1-nitropyrene in microcosms containing nonsterile estuarine sediments, and in cultures of a Mycobacterium sp. previously isolated from oil-contaminated sediments was investigated. Although mineralization of 1-nitropyrene by pure cultures of the Mycobacterium sp. totaled only 12.3% after 10 days of incubation, over 80% of the ethyl acetate extractable 14C-labeled compounds consisted of 1-nitropyrene metabolites. High pressure liquid chromatographic analysis of 1-nitropyrene degradation products indicated that two major metabolites were formed. They were identified as 1-nitropyrene cis-9,10-and 4,5-dihydrodiols, based on their UV-visible, mass and NMR spectra. Time course studies in microcosms showed that 1-nitropyrene was degraded slowly under aerobic and anaerobic conditions in estuarine sediments. Less than 1% had been converted to 14CO2 after 8 weeks of aerobic incubation. The addition of 1-nitropyrene to anaerobic sediments resulted in no 14CO2 evolution; however, the nitro group of 1-nitropyrene was reduced to form 1-aminopyrene. Although the mineralization of 1-nitropyrene in sediments was slow, the Mycobacterium sp. metabolized 1-nitropyrene in pure culture. This bacterium appears promising for the bioremediation of this ubiquitous pollutant in contaminated waste.Abbreviations DEP
Direct exposure probe
- HPLC
high pressure liquid chromatography
- GC/MS
gas chromatography/mass spectrometry
- Nitro-PAHS
nitropolycyclic aromatic hydrocarbons
- TLC
thin-layer chromatography
- UV
ultraviolet 相似文献
5.
N. Roth-Bejerano 《Planta》1980,149(3):252-256
The attachment of glycolate oxidase to the peroxisomal fraction derived from etiolated barley leaves (Hordeum vulgare L. cr. Dvir) is affected by light. The effect of red irradiation is reversed by subsequent far-red irradiation, indicating the involvement of phytochrome. This phytochrome effect is assumed to be related to phytochrome binding. Indeed, prevention by filipin (1.2·10-6 mol g-1 f wt) or cholesterol of phytochrome binding to membranes abolishes the effect of light on the interaction between glycolate oxidase and the peroxisomal fraction. Glycolate oxidase binding is affected by addition of quasi-ionophores such as gramicidin and filipin at a concentration of 0.6·10-3 mol g-1 f wt. This fact indicates that peroxisome-glycolate oxidase interaction may be affected by membrane potential. Since both ion transport and membrane potential are known to be affected by phytochrome, it is proposed that phytochrome acts in the light-induced modulation of glycolate oxidase attachment as a quasi-ionophore.Abbreviations GO
glycolate oxidase
- Pr and Pfr
phytochrome forms absorbing in red and far-red, respectively
- R and F
red and far-red irradiation
- Cumulative 20 Kp
20,000 g pellet obtained by centrifugation of the crude extract
- 1 Kp
1,000 g pellet
- 20 Kp
20,000 g pellet, obtained by centrifugation of 1 Kp supernatant
- 1 Kp, 20 Kp and cumulative 20 Kp
pellets obtained after density centrifugation through a sucrose cushion 相似文献
6.
Neal C. Robinson 《Journal of bioenergetics and biomembranes》1993,25(2):153-163
Bovine cytochromec oxidase usually contains 3–4 mol of tightly bound cardiolipin per cytochromeaa
3 complex. At least two of these cardiolipins are required for full electron transport activity. Without the tightly bound cardiolipin, cytochromec oxidase has only 40–50% of its original activity when assayed in detergents that support activity, e.g., dodecyl maltoside. By measuring the restoration of electron transport activity, functional binding constants for cardiolipin and a number of cardiolipin analogues have been evaluated (K
d,app=1 µM for cardiolipin). These binding constants agree reasonably well with direct measurement of the binding using [14C]-acetyl-cardiolipin (K
d
<0.1 µM) when the enzyme is solubilized with Triton X-100. These data are discussed in relationship to the wealth of data that is known about the association of cardiolipin with cytochromec oxidase and the other mitochrondrial electron transport complexes and transporters. 相似文献
7.
O. Farver P. Frank I. Pecht 《Biochemical and biophysical research communications》1982,108(1):273-278
The interaction between hydrogen peroxide and oxidized laccase from which the type 2 copper has been removed, was investigated. For that end, the circular dichroic spectrum of the modified enzyme has been measured in the presence of increasing concentrations of hydrogen peroxide. The characteristic band observed upon binding peroxide to native laccase is also observed for the type 2 copper depleted enzyme. However, there are several quantitative differences in the latter one. First, the intensity is lower and band width is larger. Secondly, from the titrations, it becomes apparent that the affinity for H2O2 is markedly lower than that of the native enzyme. While the affinity for the native enzyme is higher than 108 M?1, it decreases to 1·104 M?1 for the type 2 depleted enzyme. 相似文献
8.
Anthony Martonosi 《Journal of cellular biochemistry》1975,3(4):323-332
The metal ion requirement of myosin-ADP binding was investigated by use of Mn2+. Mn2+ binds to two sets of noninteracting sites on myosin which are characterized by affinity constants of 106 and 103, M−1 at 0.016 M KCl concentration. The maximum number of sites is 2 for the high affinity and 20–25 for the low affinity set. Binding of Mn2+ to the high affinity sites increases the affinity of ADP binding to myosin. F-actin inhibits ADP binding (Kiely, B., and Martonosi, A., Biochim. Biophys. Acta 172: 158–170 [1969]), but even at F-actin concentrations much higher than that required to saturate the actin binding sites of myosin or its proteolytic fragments, significant ADP binding remained. The actin insensitive portion of ADP binding was inhibited by 10−4 M inorganic pyrophosphate or ATP. The results are discussed on the basis of a model in which actin and ADP bind to myosin at distinct but interacting sites. 相似文献
9.
Endothelin-1 (ET-1) induces contraction of vascular smooth muscle through binding to endothelin type A receptor (ETAR). COS-7 cells stably expressing high levels of the ETAR were established (designated COS-7(ETAR)). The COS-7(ETAR) cell bound [125I]ET-1 with a Kd of 932 ± 161 pM and a Bmax of 74 ± 13 fmol/2 × 105 cells. [125I]ET-1 binding was inhibited by ET-1 and the ETAR antagonist BQ-610, but not by the endothelin type B receptor (ETBR) antagonist BQ-788. In clones expressing two ETAR mutants containing D46N or R53Q substitutions in the first extracellular domain of the receptor, [125I]ET-1 binding activity was dramatically reduced. This suggests that these single amino acid substitutions alter the three-dimensional structure of the ligand-binding domain of the ETAR. Using COS-7(ETAR) cell, we showed that Ca2+ or Mg2+ was essential for ET-1 binding to the ETAR and that ET-1 treatment induced postreceptor signaling, that is, intracellular accumulation of cyclic AMP (cAMP) and Ca2+ mobilization. The COS-7(ETAR) established in this study will be a useful tool for screening ET-1 antagonists for treating hypertension. 相似文献
10.
Kataoka K Tsukamoto K Kitagawa R Ito T Sakurai T 《Biochemical and biophysical research communications》2008,371(3):416-419
Met467, the axial ligand to type I Cu in a multicopper oxidase, Myrothecium verrucaria bilirubin oxidase was substituted with a non-coordinating Phe and Leu to transform the spectral and magnetic properties and oxidase activities of the enzyme into those of fungal laccases, but the mutated type I Cu center showed properties characteristic of phytocyanins, blue copper proteins with an axial coordination of Gln, due to compensatory binding of the distal Asn459 as evidenced by a double mutation. 相似文献
11.
Tritiated 3-methylindole (3MI) was administered intravenously to calves. Total and covalent bound radioactivity were measured in different tissues. Pulmonary tissue showed the highest concentration of covalent bound radioactivity. (G-3H) or (methyl-14C) 3MI became covalently bound to microsomal protein when incubated with bovine lung microsomes. This covalent binding was dependent on time, temperature, oxygen and NADPH and was inhibited by SKF-525A, cytochrome c, a carbon monoxide enriched atmosphere and cysteine. The microsomal enzyme system catalysing covalent binding of 3MI has the classical characteristics of a cytochrome P-450 dependent mixed function oxidase. Metabolic activation of 3MI to a highly electrophilic intermediate, may be fundamental in the pathogenesis of 3MI induced pulmonary damage. 相似文献
12.
《Biochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology》1987,911(2):201-208
We measured the redox potentials of frozen inactivated l-amino-acid oxidase (l-amino-acid:oxygen oxidoreductase (deaminating), EC 1.4.3.2) and inhibitor-bound (anthranilic acid) enzyme, and compared these redox properties to those of active l-amino-acid oxidase and benzoate-bound d-amino-acid oxidase (EC 1.4.3.3), respectively. The redox properties of the inactive enzyme are similar to the properties of free flavin; the potential is within 0.015 V of free flavin and no radical stabilization is seen. This corresponds to the loss of most interactions between apoprotein and flavin. In contrast, the anthranilic acid lowers the amount of radical stabilized from 85% to 35%. The potentials are still 0.150 V positive of free flavin, indicating that in the presence of inhibitor, many flavin-protein interactions remain intact. The difference between this behavior and that of d-amino-acid oxidase bound to benzoate, where the amount of radical declined from 95% to 5%, is explained on the basis of the relative tightness of binding of apoprotein to FAD. d-Amino-acid oxidase apoprotein has a relatively low Ka (106) for FAD, and benzoate has a relatively high Ka (105) for the enzyme. Therefore, the binding of benzoate increases the tightness of FAD binding to apo-d-amino-acid oxidase (1011), indicating significant changes in flavin-protein interactions. In contrast, apo-l-amino-acid oxidase binds flavin tightly (the Ka is greater than 107) and the enzyme binds to anthranilate much less tightly, with a Ka of 103. The l-amino-acid oxidase apoprotein binding to FAD is tight initially, and the binding of anthranilate changes it only slightly. Therefore, redox studies indicate that the ability of a flavoprotein to be regulated may be influenced by the strength of the interaction of flavin with the apoprotein, as well as the strength of interaction of the substrate or activator. 相似文献
13.
Summary When low concentrations (e.g. 10-6 M) of labelled 3-indoleacetic acid (14C-IAA) or -naphthaleneacetic acid (14C-NAA) are added in vitro to homogenates of corn coleoptiles, radioactivity is reversibly bound to pelletable particles. From the saturation kinetics of the binding it is possible to estimate an apparent K
M
between 10-6 M and 10-5 M and a concentration of specific sites of 10-7–10-6 M per tissue volume.The binding is auxin-specific. Among many compounds tested, only auxins and such auxin analogues that are known to interact directly with auxin in transport and/or growth were found to interfere with this binding. For instance, the growth-active d-dichlorophenoxyisopropionic acid at 10-4 M inhibits 14C-NAA binding more than the less active l-isomer.The auxin-binding fractions are practically free of DNA and cytochrome-C oxidase and contain binding sites for 1-naphthylphthalamic acid. The results are discussed in context with the hyothesis—derived mainly from physiological data—that auxin receptors are localized at the plasma membrane. 相似文献
14.
We studied the binding of (+)3H-amphetamine to membrane sites from rat hypothalamus. Our experiments demonstrate the possible existence of artefactual results in previous studies due to the inadequate use of a filtration technique. In addition, it seems that monoamine oxidase A might be a component of the complex mixture of binding sites which are recognized by (+)3H-amphetamine since harmaline and monoamine oxidase A selective inhibitors are good displacers of this ligand. 相似文献
15.
Prabir K. Dutta James Nestor Thomas G. Spiro 《Biochemical and biophysical research communications》1978,83(1):209-216
Coherent anti-Stokes Raman scattering spectra, in resonance with the isoalloxazine visible electronic transition, have been obtained down to 300 cm?1 for flavin adenine dinucleotide, riboflavin binding protein and glucose oxidase, in H2O and D2O. Several isoalloxazine vibrational modes can be identified by analogy with those of uracil. Of particular interest is a band at ~1255 cm?1 in H2O, which is replaced by another at ~1295 cm?1, in D2O. The H2O band appears to be a sensitive monitor of H-bonding of the N3 isoalloxazine proton to a protein acceptor group. It shifts down by 10 cm?1 in riboflavin binding protein, and disappears altogether in glucose oxidase. Other band shifts, of 3–5 cm?1, are similar for the two flavoproteins, and may reflect environmental changes between aqueous solution and the protein binding pockets. 相似文献
16.
Galila Agam Rivka Luria Orit Shohat Alexander Dvilansky Uri Seligsohn Avinoam Livne 《Biochimica et Biophysica Acta (BBA)/Molecular Cell Research》1985,847(3):293-300
Platelet surface glycoproteins IIb-IIIa are considered to function as the binding site for fibrinogen. Fibrinogen binding is essential for platelet aggregation and several amines have been shown to inhibit this binding. The present study compares the binding properties of 125I-fibrinogen and [3H]lysine with platelets activated by the Ca2+ ionophore A23187. Many lines of similarities in the binding properties are apparent; however, several differences were also found. The similarities are listed below and the differences are pointed out in parentheses. (a) Marked enhancement by platelet activation; (b) deficiency of binding by thrombasthenic platelets lacking the glycoproteins IIb-IIIa; (c) saturability (fibrinogen binding approaches saturation at more than 12 μM, within 10 min; lysine binding at more than 100 mM within 1 min); (d) Ca2+-dependence (at 1 mM Ca2+ lysine binding is minute and fibrinogen binding is half-saturated); (e) reversibility; the binding achieved within 10 min is exchangeable; dissociation depends upon time and external ligand concentration; (f) inhibition by the oligoamines His-Lys and Lys4; (g) inhibition by serum from a thrombasthenic patient who developed anti-glycoproteins IIb-IIIa antibodies; (h) specificity; alanine neither binds to activated platelets nor inhibits fibrinogen binding; it thus appears that the lysine which associates with activated platelets is mostly bound onto the surface of the cells rather than being incorporated; Moreover, the major site of lysine binding seems to be the complexed glycoproteins IIb-IIIa. 相似文献
17.
《生物化学与生物物理学报:生物膜》2023,1865(7):184180
In phagocytes, superoxide anion (O2−), the precursor of reactive oxygen species, is produced by the NADPH oxidase complex to kill pathogens. Phagocyte NADPH oxidase consists of the transmembrane cytochrome b558 (cyt b558) and four cytosolic components: p40phox, p47phox, p67phox, and Rac1/2. The phagocyte activation by stimuli leads to activation of signal transduction pathways. This is followed by the translocation of cytosolic components to the membrane and their association with cyt b558 to form the active enzyme.To investigate the roles of membrane-interacting domains of the cytosolic proteins in the NADPH oxidase complex assembly and activity, we used giant unilamellar phospholipid vesicles (GUV). We also used the neutrophil-like cell line PLB-985 to investigate these roles under physiological conditions. We confirmed that the isolated proteins must be activated to bind to the membrane. We showed that their membrane binding was strengthened by the presence of the other cytosolic partners, with a key role for p47phox. We also used a fused chimera consisting of p47phox(aa 1–286), p67phox(aa 1–212) and Rac1Q61L, as well as mutated versions in the p47phox PX domain and the Rac polybasic region (PB). We showed that these two domains have a crucial role in the trimera membrane-binding and in the trimera assembly to cyt b558. They also have an impact on O2.- production in vitro and in cellulo: the PX domain strongly binding to GUV made of a mix of polar lipids; and the PB region strongly binding to the plasma membrane of neutrophils and resting PLB-985 cells. 相似文献
18.
A. M. López-Colomé 《Neurochemical research》1981,6(9):1019-1033
Binding ofl-[3H]glutamate to membranes from whole chick retina and from subcellular fractions enriched with photoreceptor terminals (P1), or terminals from the inner plexiform layer (P2) was studied. Na+-dependent and Na+-independent binding to these membranes was demonstrated. Na+-independent binding was stereospecific. Kinetic analysis of the binding process indicated a single high-affinity system (K
B=0.55 M) with a capacity of approximately 20 pmoles/mg protein in all the membrane fractions. [3H]Glutamate binding to P1 and P2 fractions was effectively displaced by several structural analogues of glutamate. Glutamate diethyl-ester appreciably displaced binding, whereas kainic acid did not displace bound glutamate. Data indicate the binding of [3H]glutamate to physiologically relevant receptors in the chick retina. 相似文献
19.
Summary Inside out and right side out vesicles were used to study the sidedness of Ca binding to the human red cell membrane. It was shown that these vesicles exhibited only a limited permeability to Ca, enabling the independent characterization of Ca binding to the extracellular and cytoplasmic membrane surfaces. Ca binding was studied in 10 mM Tris HCl at pH 7.4, 22±2°C and was shown to be complete in under 5 min. Scatchard plots were made from Ca binding data obtained at free Ca concentrations in the range of 10–6 to 10–3M. Under these conditions inside out vesicles exhibit two independent binding sites for Ca with association constants of 1×105 and 6×103 M–1, and right side out vesicles exhibit three independent binding sites with association constants of 2×105, 1.4×104 and 3×102M–1. Upon the addition of 0.1M KCl a third, high affinity site was found on inside out vesicles with an association constant of 3×105, (in 0.1 M KCl). Ca binding to inside out vesicles increased nearly linearly with pH in the, range of pH 4 to pH 11, while binding to right side out vesicles remained practically unchanged in the range of pH 7 to pH 9. Progressive increase of the ionic strength of the medium by the addition of K, Mg or Tris decreased Ca binding to inside out vesicles as did the addition of ATP. Comparison of a series of cation competitors for Ca binding sites on inside out vesicles at 0.003 mM Ca showed that La was the most effective competitor of all while Cd was the most effective divalent cation competitor of those tested. Our findings suggest that the effects of low concentrations of Ca at the inner surface of the red cell membrane are mediated primarily through Ca binding to site 1 (and, possibly site 2) of inside out vesicles of which there are approximately 1.6×105 per equivalent cell. 相似文献
20.
Bioactivation of cysteine conjugates of 1-nitropyrene oxides by cysteine conjugate beta-lyase purified from Peptostreptococcus magnus.
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To determine the role of cysteine conjugate beta-lyase (beta-lyase) in the metabolism of mutagenic nitropolycyclic aromatic hydrocarbons, we determined the effect of beta-lyase on the mutagenicities and DNA binding of cysteine conjugates of 4,5-epoxy-4,5-dihydro-1-nitropyrene (1-NP 4,5-oxide) and 9,10-epoxy-9,10-dihydro-1-nitropyrene (1-NP 9,10-oxide), which are detoxified metabolites of the mutagenic compound 1-nitropyrene. We purified beta-lyase from Peptostreptococcus magnus GAI0663, since P. magnus is one of the constituents of the intestinal microflora and exhibits high levels of degrading activity with cysteine conjugates of 1-nitropyrene oxides (1-NP oxide-Cys). The activity of purified beta-lyase was optimal at pH 7.5 to 8.0, was completely inhibited by aminooxyacetic acid and hydroxylamine, and was eliminated by heating the enzyme at 55 degrees C for 5 min. The molecular weight of beta-lyase was 150,000, as determined by fast protein liquid chromatography. S-Arylcysteine conjugates were good substrates for this enzyme. As determined by the Salmonella mutagenicity test, 5 ng of beta-lyase protein increased the mutagenicity of the cysteine conjugate of 1-NP 9,10-oxide (10 nmol per plate) 4.5-fold in Salmonella typhimurium TA98 and 4.1-fold in strain TA100. However, beta-lyase had little effect on the cysteine conjugate of 1-NP 4,5-oxide (10 nmol per plate). Both conjugates exhibited only low levels of mutagenicity with nitroreductase-deficient strain TA98NR. In vitro binding of 1-NP oxide-Cys to calf thymus DNA was increased by adding purified beta-lyase or xanthine oxidase.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献