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PubMed1995

Oxidation of cysteine and methionine residues during acid hydrolysis of proteins in the presence of sodium azide.

Sodium azide is widely used as bacteriostatic agent during downstream processing of proteins. Amino acid composition analysis of protein samples, subjected to hydrolysis with hydrochloric acid in a buffer containing sodium azide, revealed the presence of cysteic acid, methionine sulfoxide, and methionine sulfone in addition to the expected reaction products. Hydrolysis with methanesulfonic acid in the presence of sodium azide resulted in detection of only methionine sulfoxide in addition to the expected products. When the proteins were hydrolyzed in a buffer containing no sodium azide or after its removal by dialysis, no oxidation products were detected (except for minor amounts of methionine sulfoxide). The generation of the particular oxidation products was affected by the concentration of sodium azide in the protein solution. Therefore, presence of sodium azide in protein samples intended for amino acid composition analysis may lead to wrong conclusions concerning oxidation of cysteine and methionine residues.

Amino Acids↗

PubMed1995

Influence of salinity on copper and azide toxicity to larval topsmelt Atherinops affinis (Ayres).

Performance of a 7-d growth and survival toxicity test protocol using larval topsmelt, Atherinops affinis (Ayres), was evaluated for copper chloride and sodium azide at representative estuarine salinities. Results showed that topsmelt are amenable to toxicity testing at estuarine salinities ranging from 5 to 34/1000 since control survival was 100% in all toxicity tests. Sensitivity to both toxicants increased at lower salinities, with the LC50s for copper ranging from 205 micrograms/L at 34/1000 to 44 micrograms/L at 10/1000, and those for sodium azide ranging from 54 mg/L at 34/1000 to 7 mg/L at 5/1000. Larval tissue osmolality decreased with increasing copper concentration relative to control fish. Copper uptake was not affected by changes in salinity. This suggests that increased sensitivity to copper was due, in part, to the increasing physiological challenge of osmoregulation. It is also possible that cupric ion concentration increased at lower salinities, resulting in reduced larval survival. It is hypothesized that increased sensitivity to azide at lower salinity was due to the interaction between azide toxicity and increasing osmotic challenge. A second experiment with azide showed that larval acclimation time did not affect the interaction between salinity and azide toxicity.

Analysis of Variance↗

PubMedDate not supplied

Three fatal sodium azide poisonings.

We report 3 cases and review the published literature on sodium azide ingestion. A 38-year-old man intentionally ingested 2 tablespoonsful of sodium azide in water and developed seizures, coma, hypotension and fatal ventricular arrhythmias within 2 hours. A 33-year-old male ingested an unknown quantity of sodium azide. In the emergency department he was unconscious and underwent immediate intubation and gastric lavage. Nitrite therapy was instituted without improvement. He remained acidotic despite bicarbonate therapy and developed hypotension which was unresponsive to pressor agents. He died approximately 8 hours after admission despite resuscitative efforts. A 52-year-old male ingested 1.5 to 2g of sodium azide and survived for 40 hours. Nitrite therapy was ineffective. The role of sodium nitrite in treating sodium azide toxicity by producing methaemoglobin which complexes with azide is discussed.

Adult↗

PubMed1988

Metabolic activation of the mutagen azide in biological systems.

Inorganic azide (N3-) mutagenicity is mediated through a metabolically synthesized organic azide, L-azidoalanine (N3-CH2-CH(-NH2)-COOH). L-Azidoalanine appears to be formed by the action of O-acetylserine (thiol)-Lyase (EC 4.2.99.8) using O-acetylserine and azide as substrates. In both plants and bacteria tested, azide substitutes for the natural substrate sulfide (S2-) in this reaction. Azide (L-azidoalanine) mutagenesis is highly attenuated by a deficiency in the excision of UV-like DNA damage (uvr-). Thus a premutation lesion recognizable by the bacterial excision-repair enzymes must be formed. Mutagenesis appears to proceed from this by 'direct mispairing' pathway. Azide (L-azidoalanine) mutagenicity is highly specific and involves a stereoselective process, but the molecular nature of the specificity has not been determined.

Alanine↗

PubMed2000

Mutagenicity of sodium azide and its metabolite azidoalanine in Drosophila melanogaster.

The mutagenic and toxic activities of sodium azide (NaN(3) ) and its organic metabolite L-azidoalanine [N(3)-CH(2)-CH(NH)(2)-COOH] were examined in the different stages of spermatogenesis in Drosophila melanogaster. Both azide and azidoalanine were toxic to the injected males, but azidoalanine was significantly less toxic than sodium azide. Following the injection with 0.2 microl of these compounds in the hemocoel of young adult wild-type males, the minimum concentrations of these compounds with complete toxic effects (zero survival) were 40 mM sodium azide and 160 mM azidoalanine. Sex-linked recessive lethals were scored by the Muller-5 method in three successive broods, representing sperms (brood A), spermatids (brood B), and a compiled group of meiotic and premeiotic germ cell stages (brood C). The results provide strong experimental evidence that azidoalanine is significantly (p<0.01) mutagenic to all stages of spermatogenesis in Drosophila melanogaster. Sodium azide, however, was not significantly (p>0.05) mutagenic and did not increase the rate of sex-linked recessive lethals over those produced by the control group injected with 0.45% NaCl. These results indicate the requirement of metabolic activation of azide in Drosophila as a prerequisite for its mutagenic effects.

Alanine↗

PubMed1988

Azide-binding studies reveal type 3 copper heterogeneity in ascorbate oxidase from the green zucchini squash (Cucurbita pepo).

Titration of native ascorbate oxidase from green zucchini squash (Cucurbita pepo) with azide in 0.1 M-phosphate buffer, pH 6.8, exhibits a biphasic spectral behaviour. Binding of the anion with 'high affinity' (K greater than 5000 M-1) produces a broad increase of absorption in the 400-500 nm region (delta epsilon approximately 1000 M-1.cm-1) and c.d. activity in the 300-450 nm region, whereas azide binding with 'low affinity' (K approximately 100 M-1) is characterized by an intense absorption band at 420 nm (delta epsilon = 6000 M-1.cm-1), corresponding to negative c.d. activity and a decrease of absorption at 330 nm (delta epsilon = -2000 M-1.cm-1). The high-affinity binding involves a minor fraction of the protein containing Type 3 copper in the reduced state, and the spectral features of this azide adduct can be eliminated by treatment of the native enzyme with small amounts of H2O2, followed by dialysis before azide addition. As shown by e.s.r. spectroscopy, Type 2 copper is involved in both types of binding, its signal being converted into that of a species with small hyperfine splitting constant [12 mT (approximately 120 G)] in the case of the low-affinity azide adduct. The spectral similarities of the two types of azide adducts with the corresponding adducts formed by native laccase, which also exhibits Type 3 copper heterogeneity, are discussed.

Ascorbate Oxidase↗

PubMed1995

The inhibitory effect of 3-amino-1,2,4-triazole on relaxation induced by hydroxylamine and sodium azide but not hydrogen peroxide or glyceryl trinitrate in rat aorta.

1. In this study we investigated the role of catalase in relaxation induced by hydroxylamine, sodium azide, glyceryl trinitrate and hydrogen peroxide in isolated rings of rat aorta. 2. Hydrogen peroxide (1 microM-1 mM)-induced concentration-dependent relaxation of phenylephrine (PE)-induced tone in endothelium-containing rings. In endothelium-denuded rings, however, higher concentrations (30 microM-1 mM) of hydrogen peroxide were required to produce relaxation. The endothelium-dependent component of hydrogen peroxide-induced relaxation was abolished following pretreatment with N(O)-nitro-L-arginine methyl ester (L-NAME, 30 microM). L-NAME (30 microM) had no effect, however, on hydrogen peroxide-induced relaxation in endothelium-denuded rings. 3. Pretreatment of endothelium-denuded rings with catalase (1000 u ml-1) blocked relaxation induced by hydrogen peroxide (10 microM-1 mM). The ability of catalase to inhibit hydrogen peroxide-induced relaxation was partially blocked following incubation with 3-amino-1,2, 4-triazole (AT, 50 mM) for 30 min and completely blocked at 90 min. 4. Pretreatment of endothelium-denuded rings with methylene blue (MeB, 30 microM) inhibited relaxation induced by hydrogen peroxide (10 microM-1 mM), sodium azide (1-300 nM), hydroxylamine (1-300 nM) and glyceryl trinitrate (1-100 nM) suggesting that each acted by stimulation of soluble guanylate cyclase. 5. Pretreatment of endothelium-denuded rings with AT (1-50 mM, 90 min) to inhibit endogenous catalase blocked relaxation induced by sodium azide (1-300 nM) and hydroxylamine (1-300 nM) but had no effect on relaxation induced by hydrogen peroxide (10 microM-1 mM) or glyceryl trinitrate (1-100 nM). 6. In a cell-free system, incubation of sodium azide (10 microM-3 mM) and hydroxylamine (10 microM-30 mM) but not glyceryl trinitrate (10 microM-1 mM) with catalase (1000 u ml-1) in the presence of hydrogen peroxide (1 mM) led to production of nitrite, a major breakdown product of nitric oxide. AT (1-100 mM) inhibited, in a concentration-dependent manner, the formation of nitrite from azide in the presence of hydrogen peroxide. 7. These data suggest that metabolism by catalase plays an important role in the relaxation induced by hydroxylamine and sodium azide in isolated rings of rat aorta. Relaxation appears to be due to formation of nitric oxide and activation of soluble guanylate cyclase. In contrast, metabolism by catalase does not appear to be involved in the relaxant actions of hydrogen peroxide or glyceryl trinitrate.

Amitrole↗

PubMed1996

Production of sodium azide inactivating substance by resistant mutants of Salmonella typhimurium and other bacteria.

We have found that azide-resistant mutants of Salmonella typhimurium and of other bacteria studied produce a substance which inactivates the azide. The production of this substance was proved by the demonstration of a satellite growth of azide-sensitive cells around colonies of azide-resistant mutants and by testing azide inactivating properties of culture filtrates of the azide-resistant strains. The same substance was found to be present in lower concentrations in culture filtrates of wild-type sensitive strains. In both cultures of sensitive strains, it was apparently produced by the resistant mutants and not by the sensitive cells. The substance does not pass across a dialysis membrane and is heat stable. It has a high molecular weight but is not a protein.

Azides↗

PubMed1998

NO donors with antithrombotic and vasodilating activities, Part 23. Organic azides.

Twenty eight organic azides were synthesized and tested for their antithrombotic and blood pressure lowering activities in rats (60 mg/kg, p.o.). In fifteen compounds significant antithrombotic effects were observed. In thirteen cases a significant lowering of the blood pressure of spontaneously hypertensive rats (SHR) was seen. The peak activities in both systems were found for hexyl azide (4), 2-phenylethyl azide (14), and 4-pyridinecarboxylic acid azide (23). In these compounds the inhibition of thrombus formation in mesenteric arterioles was > 20%. The lowering of blood pressure was > 10% and long lasting (> 6 h) in 4 and 14 while 23 had a shorter duration of action (approximately 4 h). In two classes of azides, namely branched aliphatic azides (e.g. 2-azidopentane 9) and aliphatic carbonyl derivatives (e.g. benzoyl-azido-methane 17), only antithrombotic properties were observed. A lack of endothelial metabolism is suggested to be the reason for this therapeutically favorable behaviour.

Animals↗

PubMed1986

Chromium (VI) comutagenesis: characterization of the interaction of K2CrO4 with azide.

In a previous report chromate potentiated the mutagenicity of sodium azide, apparently by affecting repair and/or replication of DNA. Further evidence in support of such a mechanism for chromate potentiation is reported here. Chromate does not react directly with azide or its major mutagenic metabolite, azidoalanine, eliminating such reactions as possible mechanisms for potentiation. Further, azide was unable to potentiate the mutagenicity of chromate in Salmonella typhimurium strain TA104, which is sensitive to chromate mutagenicity but not to azide. Thus, it appears that the potentiation is not due to an action of azide in modulating chromate mutagenicity. Finally, the interaction was not altered by deficiency in recA gene product in S typhimurium GW19, nor by enhancement of SOS repair in the pKM101 containing strain TA100. Thus, induction of recA-dependent functions seems to play no role in the comutagenic actions of chromate. The simplest explanation for potentiation seems to be that chromate is able either to limit error-free recovery from azide-induced DNA damage or to promote error-prone repair or error-prone processing at sites of lesions.

Alanine↗

PubMed1985

Interaction of azide with beef heart mitochondrial ATPase.

This study examined the inhibition of azide as a probe of the magnesium regulation of beef heart mitochondrial ATPase (F1) catalysis. Azide elicited a slow hysteretic effect on both ATP and ITP hydrolysis of F1. This hysteretic effect was shown to be due to the consecutive binding of magnesium and azide, and to be independent of catalytic turnover. The azide binding site was also shown to be separate from the anion binding HCO3- site on F1. The results presented indicate that metal binding is important in the inhibition of the hydrolytic activity and regulation of F1. A model is presented which is consistent with the hysteretic inhibition of F1 by azide, in which there is a slow equilibration between free enzyme and the enzyme-magnesium-azide complex.

Animals↗

PubMed1996

Two bacteriorhodopsin M intermediates differing in accesibility of the Schiff base for azide.

Glutaraldehyde treatment leads to the inhibition (i) of the M intermediate decay in wild-type bacteriorhodopsin (bR) and (ii) of the azide-facilitated M decay in the D96N mutant bR. LuCl3 is shown to be a more potent inhibitor of both processes. Glycerol and sucrose are also inhibitors. None of these agents change the linearity of the azide concentration dependency of the M decay in the D96N mutant but they do shift this dependency to higher azide concentrations. It is concluded that the two M forms are in equilibrium. These M forms differ in the accessibility of the Schiff base for azide and, probably, also for water molecules. The above-mentioned agents shift the equilibrium toward the less accessible M form. The data obtained are in line with the model of azide action as the penetrating proton donor and can hardly be realized within the framework of the model of Le Coutre et al. [(1995) Proc. Natl. Acad. Sci. USA 92, 4962-4966] which assumes that a bound anionic form of azide catalyzes proton transfer to the Schiff base.

Azides↗

PubMed1980

Effects of pH on the mutagenicity of sodium azide in Neurospora crassa and Salmonella typhimurium.

Sodium azide at various pH values did not cause a significant increase in the frequency of forward mutation above the control frequency at the adenine-3 (ad-3) region in resting conidia and in conidia from growing cultures of heterokaryons 12 and 59 of Neurospora crassa. Conidia from ad-3 mutants were plated with sodium azide at various pH values, and no obvious increase in reverse mutation above the controls was observed. Data are presented showing that sodium azide at pH 3 is inactivating conidia by interacting with the cytoplasma rather than the nucleus, and this may be the primary reasons that no mutation at the ad-3 region was detected. The dependence of sodium azide mutagenicity on pH was investigated in histidine-requiring mutants of Salmonella typhimurium using a suspension test. There were no significant differences in the reversion frequencies among the pH values (3-8) tested. Thus, no pH dependence is associated with sodium azide mutagenicity, nor are growth and/or DNA replication required for mutagenicity by sodium azide, in S. typhimurium.

Adenine↗

PubMed1992

Chronic sodium azide treatment impairs learning of the Morris water maze task.

A reduction in the activity of cytochrome oxidase, a respiratory chain enzyme, has been recently identified in mitochondria from blood platelets and postmortem brain tissue from Alzheimer's disease (AD) patients. We have developed an animal model of this deficit in rats by chronic subcutaneous infusion of sodium azide, a selective inhibitor of cytochrome oxidase, delivered via Alzet 2ML4 osmotic minipumps. In previous work, azide-treated rats were impaired in an appetitively motivated spatial learning task, the radial arm maze. In the present investigation, we tested male Sprague-Dawley rats (350-400 g), which were tonically infused with azide or saline, on an aversively motivated spatial task, the Morris water maze. Azide-treated rats were impaired on both acquisition and retention of this task, without showing evidence of a motor impairment. Thus, the present results are consistent with previous findings showing that chronic azide treatment produces a learning and memory deficit. These findings strengthen the hypothesis that azide treatment in rats produces a useful animal model of some aspects of AD.

Animals↗

PubMed2001

Catalytic inhibition of DNA topoisomerase IIalpha by sodium azide.

It has been demonstrated previously that sodium azide reduces the clastogenicity of several DNA topoisomerase II (topo II) poisons in cultured mammalian cells. These studies suggested that azide may be a catalytic topo II inhibitor. Azide interferes with mitochondrial production of ATP and is also known to inhibit cellular ATPases. Since topo II requires ATP for catalytic activity (enzyme turnover), it seemed likely that interference with ATP levels or ATP catabolism was the underlying mechanism of topo II inactivation; however, this has not been examined in living cells under conditions where the endogenous topo II is active on genomic DNA. The present studies were carried out to verify that azide inhibits endogenous topo II in cells. We show that azide blocks both decatenation and relaxation activity of purified topo II in a concentration dependent manner and reduces topoII/DNA covalent complex formation in cells. From these studies, it is concluded that sodium azide catalytically inactivates topo II via an ATP-sensitive process.

Antigens, Neoplasm↗

PubMedDate not supplied

Chlorinated phenyl azides as photolabeling reagents. Synthesis of an ortho,ortho'-dichlorinated arylazido PCP receptor ligand.

The enhanced photolabeling properties of chlorinated phenyl azides are demonstrated by the synthesis and photolysis of methyl 4-azido-2,3,5,6-tetrachlorobenzoate (3) and methyl 4-azido-3,5-dichlorobenzoate (4). Photolysis of azide 3 in 1 M diethylamine/cyclohexane as the trapping medium gave 34% NH-insertion product. Similar photolysis of azide 4 gave 35% NH insertion product. These results demonstrate that chlorinated phenyl azides are significantly better at undergoing NH insertion than nonhalogenated analogs and suggest that improvement of existing aryl azide-based photolabels might be achieved by introduction of chlorine atoms on either side of the azide group. As an application, 3-azido-2,4-dichloro-10,5-(iminomethano)-10,11-dihydro-5H- dibenzo[a,d]cycloheptene (19), an analog of the potent PCP receptor ligand IDDC (14), was synthesized and its affinity for the PCP receptor was determined to be 6.3 +/- 0.7 microM (IC50 against [3H]MK801).

Affinity Labels↗

PubMed1994

FTIR analysis of the interaction of azide with horse heart myoglobin variants.

The interaction of azide with variants of horse heart myoglobin (Mb) has been characterized by Fourier transform infrared (FTIR), electron paramagnetic resonance (EPR), and UV-VIS absorption spectroscopy and by molecular modeling calculations. Distal histidine variants (His64Thr, His64Ile, His64Lys) and charged surface variants (Val67Arg, Lys45Glu, Lys45Glu/Lys63Glu) were included in this study. All variants, with the exception of Val67Arg, have a lower azide affinity than the wild-type protein. Analysis of the temperature dependence of the FTIR spectra (277-313 K) revealed that the wild-type protein and all variants exhibit a high-spin/low-spin equilibrium. Introduction of positively charged amino acid residues shifts nu max for the low-spin form to higher energy while negatively charged residues shifted this maximum to lower energy. The low azide binding affinity exhibited by the His64Thr and His64Ile variants is accompanied by a shift of the nu max for the low-spin infrared band to lower energy and by a significant increase in the corresponding half-bandwidths. This observation indicates greater mobility of the bound azide ligand in these variants. The His64Lys variant exhibits two infrared bands attributable to low-spin forms that are assigned to two different conformations of the lysyl residue. In one conformation, the lysine is proposed to form a hydrogen bond with the bound azide similar to that proposed to occur between the distal histidine and bound azide, and in the other conformation no interaction occurs.

Animals↗

PubMed1998

Fourier transform infrared analysis of the interaction of azide with the active site of oxidized and reduced bovine Cu,Zn superoxide dismutase.

Binding of azide to the native and arginine-modified bovine Cu,Zn superoxide dismutase in the oxidized and reduced form and to the copper-free derivative has been investigated by Fourier transform infrared spectroscopy. The antisymmetric stretching band of the azide is shifted to higher energy upon coordination to the copper atom of the oxidized form of the native enzyme. Similar spectral changes occur upon interaction of the anion with the Cu-diethylenetriamine model compound. On the other hand, interaction of azide with the native reduced form of the enzyme results in a band shift toward lower energy with respect to the free anion band. The same shift is observed after reaction of the azide with free lysine or arginine but not when it is reacted with other amino acid residues. The antisymmetric band of the azide is not perturbed by addition of the reduced arginine-modified enzyme; it is likely shifted toward higher energy upon addition of oxidized arginine-modified enzyme while it is again shifted toward lower energy in the presence of the copper-free derivative of the unmodified enzyme. It is concluded that azide does not directly coordinate to the copper in the reduced form of Cu,Zn superoxide dismutase but it remains in the active-site pocket in electrostatic interaction with the guanidinium group of Arg141, which is an invariant residue in this class of enzymes.

Animals↗