SEARCH · PubMed Health

Results for “HYDROCYANIC ACID”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 181 records · Page 10Linked to original sources

PubMed2001

The hydroxynitrile lyase from almond: a lyase that looks like an oxidoreductase.

BACKGROUND: Cyanogenesis is a defense process of several thousand plant species. Hydroxynitrile lyase, a key enzyme of this process, cleaves a cyanohydrin into hydrocyanic acid and the corresponding aldehyde or ketone. The reverse reaction constitutes an important tool in biocatalysis. Different classes of hydroxynitrile lyases have convergently evolved from FAD-dependent oxidoreductases, alpha/beta hydrolases, and alcohol dehydrogenases. The FAD-dependent hydroxynitrile lyases (FAD-HNLs) carry a flavin cofactor whose redox properties appear to be unimportant for catalysis. RESULTS: We have determined the crystal structure of a 61 kDa hydroxynitrile lyase isoenzyme from Prunus amygdalus (PaHNL1) to 1.5 A resolution. Clear electron density originating from four glycosylation sites could be observed. As concerns the overall protein fold including the FAD cofactor, PaHNL1 belongs to the family of GMC oxidoreductases. The active site for the HNL reaction is probably at a very similar position as the active sites in homologous oxidases. CONCLUSIONS: There is strong evidence from the structure and the reaction product that FAD-dependent hydroxynitrile lyases have evolved from an aryl alcohol oxidizing precursor. Since key residues implicated in oxidoreductase activity are also present in PaHNL1, it is not obvious why this enzyme shows no oxidase activity. Similarly, features proposed to be relevant for hydroxy-nitrile lyase activity in other hydroxynitrile lyases, i.e., a general base and a positive charge to stabilize the cyanide, are not obviously present in the putative active site of PaHNL1. Therefore, the reason for its HNL activity is far from being well understood at this point.

Aldehyde-Lyases↗

PubMed1998

New polyazaporphine chemistry for the origin of life.

Molecular orbital spectral predictions suggest that 2,5,7,10,12,15,17,20-octaaza-21H, 23H-porphine has a visible spectral range closely matching that of chlorophyll-a. Since the octaazaporphine is, in its core, a simple derivative of an (HCN)12 oligomer, this fact, together with its spectral properties, would suggest that it occupies a high rank as a primordial porphinic solar energy transducer for photochemistry essential to life's formation. The demonstration that the mass 324 hexahydrooctaazaporphine is formed in protic media by the cyclotetramerization of imidazol-4-aminohydroxonium ion or the derived nitrenium ion, and that a mass 318 species consonant with that of the Huckel aromatic octaazaporphine is observed in the course of these studies, strongly supports the proposed octaazaporphine synthesis in a prebiotic hydrocyanic acid milieu.

Chlorophyll↗

PubMed1991

The effect of a nutritionally-balanced cassava (Manihot esculenta Crantz) diet on endocrine function using the dog as a model. 2. Thyroid.

Growing dogs were divided into three groups and were fed on nutritionally-balanced diets. Control dogs were fed on a rice diet, the cassava (gari) group ate a diet in which gari provided the carbohydrate source, while the rice + cyanide group consumed the rice diet to which hydrocyanic acid (equivalent to that present in gari) was added. Each group consumed its diet for 14 weeks, during which plasma thiocyanate concentration and total serum triiodothyronine (T3) were monitored. At the end of the experiment the concentrations of the plasma free amino acids phenylalanine and tyrosine, the thyroid weights and histology were determined. While plasma thiocyanate remained undetectable in control dogs, animals consuming both gari and rice + cyanide generated significant amounts. In the control dogs and the gari group, total serum T3 increased 40 and 38.8% respectively from the basal level by the end of the period (P less than 0.02). In contrast there was a decrease in T3 by 36% in the dogs fed on rice + cyanide (P less than 0.05). This group also showed significant thyroid enlargement and a histological picture consistent with parenchymatous goitre, whereas the gari group was essentially normal. The relatively low mean thyroid weight, the rise in total serum T3 level and the normal histological appearance of the gland indicate that dogs that consumed the gari diet were essentially normal with respect to their thyroid function, in spite of their high blood thiocyanate content. In contrast, dogs that consumed rice with cyanide suffered from hypothyroidism and goitre.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed2001

The enhancement of the nutritive value of mango seed kernels for poultry by thermal treatment and radiation processing.

Raw seed kernels of local mango varieties (Magnifera indica L.) were analyzed for composition, levels of trypsin inhibitors, tannins, cyanogenetic glucosides, in vitro protein digestibility and apparent metabolizable energy (AMEN) as being effected by boiling, autoclaving as well as irradiation at 5, 10, 15, and 20 kGy. The air-dry mango seed kernels (MSK) contained CP 70 g kg-1, EE 128 g kg-1, and tannins 67 g kg-1. Compared with raw kernels the contents of trypsin inhibitory activity (30 TIU g-1) and cyanogenetic glucosides, measured as hydrocyanic acid (71 mg kg-1), were lowered by boiling, autoclaving and radiation treatments. Tannin content (67.2 g kg-1 in raw kernels) was decreased only by boiling or autoclaving, but irradiation did not introduce any effect. The low in vitro protein digestibility and AMEN values of raw MSK were enhanced by processing. The improvements were paralleled to reductions in trypsin inhibitory activity, cyanogenetic glucosides and tannin contents. Greater improvements were noticed with boiling and autoclaving than with irradiation alone. Autoclaving for 30 min plus irradiation treatment up to 20 kGy increased the in vitro protein digestibility and AMEN by 139% and 72%, respectively. These results indicate that tannins, trypsin inhibitors and cyanogenetic glucosides are responsible for the poor nutritive value of MSK. The effects of feeding 200 g kg-1 raw or processed MSK on the performance of broiler chicks were examined. The inclusion of raw kernel affected body weight gain and feed consumption, while weight gain of birds fed the autoclaved (30 min) plus irradiated (20 kGy) kernels was significantly more improved than by the other treatments. However, feed conversion ratio was not significantly different between groups fed the processed MSK. The results showed that the combination of autoclaving for 30 min plus irradiation up to 20 kGy upgraded the nutritive value more than the other tested treatments and that this method is most effective in processing MSK to be used as animal feed.

Anacardiaceae↗

PubMed1998

A new specific method to detect cyanide in body fluids, especially whole blood, by fluorimetry.

This study shows a simple, rapid, and specific method for the quantitative determination of cyanide ion in body fluids, especially blood, by fluorimetry. It is based upon the transformation of cyanide ion into hydrocyanic acid, which then reacts with 2,3-naphthalenedialdehyde and taurine in a self-contained system. The 1-cyano-2-benzoisoindole derivate thus formed is suitable for fluorimetric measurement (lambdaEX = 418 nm; lambdaEM = 460 nm). The fluorescence intensity can be determined by spectrophotometry or by high-performance liquid chromatography (HPLC) with fluorescence detection. The detection limit is 0.002 microg/mL. Linearity was excellent from 0.002 to 1 microg/mL for spectrophotometry and from 0.002 to 5 microg/mL for HPLC with fluorescence detection. The coefficient of variation for repeatability was 8% or less. Thiocyanate and sulfide did not interfere, even at high concentrations (200 microg/mL). The method was applicable to whole blood, so it should be suitable for both clinical and forensic purposes.

Body Fluids↗

PubMed1987

Digestibility of boiled and oven-dried cassava in infants and small children.

Boiled fresh cassava or oven-dried cassava flour provided 50% of the energy and less than 10% of the protein in diets of convalescent malnourished infants; casein was added to complete 8% of energy as protein, and vegetable oil (soybean-cottonseed) was added to make 20% of energy as fat. Despite high wet weights of feces (172 +/- 42 and 214 +/- 41 g/d), their dry weights (20 +/- 3 and 22 +/- 2 g/d) and their energy (6.9 +/- 0.7 and 7.6 +/- 0.5% of intake) and nitrogen (17 +/- 3 and 20 +/- 3% of intake) contents were low, and their fat content (4.4 +/- 1.3 and 5.2 +/- 1.2% of intake) was very low. Cassava is a surprisingly effective source of energy which interferes little or not at all with digestion of added protein and fat in weaning diets. For its safe use, it is important that home or industrial processing almost completely eliminate its potential hydrocyanic acid content, and that a good quality protein supplement be consumed regularly in nutritionally adequate amounts.

Body Weight↗

PubMed2002

The active site of hydroxynitrile lyase from Prunus amygdalus: modeling studies provide new insights into the mechanism of cyanogenesis.

The FAD-dependent hydroxynitrile lyase from almond (Prunus amygdalus, PaHNL) catalyzes the cleavage of R-mandelonitrile into benzaldehyde and hydrocyanic acid. Catalysis of the reverse reaction-the enantiospecific formation of alpha-hydroxynitriles--is now widely utilized in organic syntheses as one of the few industrially relevant examples of enzyme-mediated C-C bond formation. Starting from the recently determined X-ray crystal structure, systematic docking calculations with the natural substrate were used to locate the active site of the enzyme and to identify amino acid residues involved in substrate binding and catalysis. Analysis of the modeled substrate complexes supports an enzymatic mechanism that includes the flavin cofactor as a mere "spectator" of the reaction and relies on general acid/base catalysis by the conserved His-497. Stabilization of the negative charge of the cyanide ion is accomplished by a pronounced positive electrostatic potential at the binding site. PaHNL activity requires the FAD cofactor to be bound in its oxidized form, and calculations of the pKa of enzyme-bound HCN showed that the observed inactivation upon cofactor reduction is largely caused by the reversal of the electrostatic potential within the active site. The suggested mechanism closely resembles the one proposed for the FAD-independent, and structurally unrelated HNL from Hevea brasiliensis. Although the actual amino acid residues involved in the catalytic cycle are completely different in the two enzymes, a common motif for the mechanism of cyanogenesis (general acid/base catalysis plus electrostatic stabilization of the cyanide ion) becomes evident.

Aldehyde-Lyases↗

PubMed2006

Formation of water-soluble metal cyanide complexes from solid minerals by Pseudomonas plecoglossicida.

A few Pseudomonas species are able to form hydrocyanic acid (HCN), particularly when grown under glycine-rich conditions. In the presence of metals, cyanide can form water-soluble metal complexes of high chemical stability. We studied the possibility to mobilize metals as cyanide complexes from solid minerals using HCN-forming microorganisms. Pseudomonas plecoglossicida was cultivated in the presence of copper- and nickel-containing solid minerals. On powdered elemental nickel, fast HCN generation within the first 12 h of incubation was observed and water-soluble tetracyanaonickelate was formed. Cuprite, tenorite, chrysocolla, malachite, bornite, turquoise, millerite, pentlandite as well as shredded electronic scrap was also subjected to a biological treatment. Maximum concentrations of cyanide-complexed copper corresponded to a solubilization of 42% and 27% when P. plecoglossicida was grown in the presence of cuprite or tenorite, respectively. Crystal system, metal oxidation state and mineral hydrophobicity might have a significant influence on metal mobilization. However, it was not possible to allocate metal mobilization to a single mineral property. Cyanide-complexed gold was detected during growth on manually cut circuit boards. Maximum dicyanoaurate concentration corresponded to a 68.5% dissolution of the total gold added. These findings represent a novel type of microbial mobilization of nickel and copper from solid minerals based on the ability of certain microbes to form HCN.

Copper↗

PubMed1992

Mechanisms underlying Phalaris aquatica "sudden death" syndrome in sheep.

Twenty outbreaks of Phalaris aquatica "sudden death" syndrome in sheep were investigated between 1981 and 1991. Four were confirmed and one was suspected, to be a cardiac disorder; 5 were confirmed and 3 were suspected, to be a polioencephalomalacic disorder; the aetiology of the remaining 7 outbreaks could not be determined. Potentially toxic levels of hydrocyanic acid (20 to 36 mg/100 g) were measured in the 3 toxic phalaris pastures tested. The measurement of potentially toxic levels of nitrate nitrogen (2920 micrograms/g) in toxic phalaris pastures by others, was noted. It is suggested that phalaris "sudden death" syndrome could have as many as 4 different underlying mechanisms, and that these might reflect the presence in the plant of a cardio-respiratory toxin, a thiaminase and amine co-substate, cyanogenic compounds, and nitrate compounds.

Animals↗

PubMed1968

Origin of cyanide in cultures of a psychrophilic basidiomycete.

An unidentified psychrophilic basidiomycete used valine and isoleucine as precursors to hydrocyanic acid (HCN). As probable intermediates in the pathway from valine and isoleucine two cyanogenic glucosides, linamarin and lotaustralin, were demonstrated in fungus cultures. The fungus contained two beta-glucosidases and an oxynitrilase which, acting together, were capable of releasing cyanide from both linamarin and lotaustralin. The two beta-glucosidases were purified and compared as to pH optimum, Michaelis constant, energy of activation, thermal stability, and substrate specificity. The products of methyl ethyl ketone cyanohydrin and acetone cyanohydrin dissociation by the oxynitrilase were demonstrated to be HCN together with methyl ethyl ketone and acetone, respectively. The oxynitrilase attacked aliphatic hydroxynitriles, but showed no activity on aromatic hydroxynitriles.

Amino Acids↗

PubMed1999

Pseudomonas aeruginosa (GRC1) as a strong antagonist of Macrophomina phaseolina and Fusarium oxysporum.

A plant growth promotory bacterial strain, isolated from the potato rhizosphere, was characterized as Pseudomonas aeruginosa (GRC1). The isolate produced an hydroxamate type of siderophore after 48 h of incubation on tryptic soy medium under iron deficient conditions. The in vitro antifungal activity of P. aeruginosa was tested against two soil-borne plant pathogens, Macrophomina phaseolina and Fusarium oxysporum. The antagonistic behaviour of the isolate was tested by dual culture technique. The growth inhibition of M. phaseolina and F. oxysporum was 74.1% and 70.5%, respectively, after 5 days of incubation. The production of hydrocyanic acid and indole acetic acid was also recorded under normal growth conditions.

Fusarium↗

PubMed1997

[Comparison of two extraction methods for maxingshigan decoction].

The semi-bionic extraction and the extraction with water, two methods for the Maxingshigan Decoction, were compared. The results show that the semi-bionic extraction is superior to the extraction with water in the yield of ephedrine, hydrocyanic acid, glycyrrhetinic acid, calcium ion and extract.

Calcium↗

PubMed2001

[Cloning, expression and preliminary application of a alpha-hydroxynitrile lyase from cassave].

alpha-Hydroxynitrile lyase (ME-HNLs, E.C. 4.1.2.3.37) from the cyanogenic crop cassava(Manihot esculentz, Crantz) catalyze the condensation of hydrocyanic acid and aldehydes or ketone into (s)-cyanohydrins, which are valuable starting material for various optically active compounds, such as pharmaceuticals and agrochemicals. The cDNA of a ME-HNL were obtained by RT-PCR and cloned. The sequencing result for the cDNA showed that the sequence encoded for the ME-HNL was inconsistent with all those which are published, such as hnl10, hnl24, hnl4. The full sequence analysis demonstrated that the cloned cDNA was about 75.2%, 79.8%, 99.2% homologous to other three reported HNL genes from cassava, respectively, among which the last was the same to the cloned gene except the five base substitution at the site 142, 337, 476, 634 and 636, respectively. The two base substitutions lead to change the amino acid sequence, i.e., Ser113-->Gly113, Phe158-->Tyr158. To construct the recombinant plasmid pET30a-hnl, the cDNA was inserted into an expression vector pET30a. After transformation of pET30a-hnl and induction with IPTG, the ME-HNL was efficiently expressed in E. coli. BL21 (DE3) and reached over 2100 units/L of culture with the specific activity 8.5 u/mg protein. By one simple treatment, incubating 10 minutes at 70 degrees C, the recombinant ME-HNL may be used as an catalyst for production of (S)-mandelonitrile with enantiomeric excess of 95.2% and 98.2% yield.

Aldehyde-Lyases↗

PubMed1999

[Memoirs on Chlorodyne and Shinyaku].

Dr. J. Collins Browne, a British army surgeon in India, invented a secret remedy for cholera-infected patients in the fifth decade of the 19th century. After his resignation from the army, the formula was given to a pharmacist in London for the purpose of manufacture and marketing as a patented medicine named Chlorodyne. Chlorodyne was well-accepted as paregoric for several decades. The formula of Chlorodyne was adopted in the 3rd Revision of the British Pharmacopoeia (1885) as "Compound Tincture of Chloroform and Morphine." In 1906, the 3rd Revision of Japanese Pharmacopoeia listed "Compound Tincture and Morphine" according to the formula of the 4th Revision of British Pharmacopoeia (1898). References written in 1870 and 1873 recorded the importation of Chlorodyne to Japan. In 1871, Dr. Jyun Matsumoto, Chief Military Surgeon Major General advised the manufacturers of traditional medicines to produce patented medicines to spread in western countries. Preparations of formula seeming to resemble Chlorodyne was named "Shinyaku" and were marketed from 1872. The name Shinyaku represented a medicine of marvellous efficacy, because the word split, Shin and Yaku, means "divine or almighty" and "medicine," respectively. Although the orginal formula of Shinyaku was not preserved, modifications of the formula were made to meet legal restrictions over the change of time. Needless to say, Morphine hydrochloride, Diluted hydrocyanic acid and tincture of Indian hemp were replaced with other ingredients to assure safety and lately Chloroform deleted from the formula as well. Shinyaku enjoyed good sales for a long time owing to its efficacy of restorative and refrigerant.

Chloroform↗

PubMed1990

[A method of cleaning overalls contaminated with sodium cyanide].

The contributors propose a new technique of cleaning overalls in galvanic shops from crystalline natrium cyanide (NC) and alkaline solutions. The technique includes washing in hot 0.05% syntamide-5 solution for 4-5 min., double rinsing and centrifuging. The remaining quantity of NC on washed overalls does not exceed 0.02 mg/m2 (evaluated in hydrocyanic acid). Subsequent contaminations of the overalls with NC do not entail the accumulation of NC residual content. The physical and chemical characteristics of this type of overall washing are more preferable as compared to those attained through soaking in ferric sulfate solution.

Cyanides↗

PubMed1975

[Stability of amphetaminil. 2. In vivo studies].

The metabolism of radioactively labelled alpha-phenyl-alpha-N-(beta-phenyl-isopropyl)-aminoacetonitrile (amphetaminil, AN 1-R) (tritium-labelled in the amphetamine-part, 14C-labelled in the benzaldehyde-part of the molecule) in the rat was examined. In the body amphetaminil is cleft very quickly into the original compounds of its chemical synthesis (amphetamine, benzaldehyde and hydrocyanic acid) independent of the mode of application (i.p. or oral). Blood: In the interval from 5-90 min after application of amphetaminil only 1-2 percent of the total radioactivity are received from amphetaminil. The main part of the tritium- and 14C-radioactivity is distributed among amphetamine, p-OH-amphetamineglucuronide and hippuric acid. Brain: In the brain only a minimum amount of amphetaminil can be present, if any. The share of amphetamine of the total activity amounts to more than 90 percent. Adipose tissue: In the adipose tissue the ratio of the two isotopes of the substances extracted at pH 5 is almost equal to that of the administered amphetaminil. It seems that the substance is enriched there because of its pronounced lipophilia. After i.p. application the concentration is about 12 times higher than after oral application. Urine: In the urine there could be detected amphetamine, p-OH-amphetamineglucuronide and hippuric acid but no amphetaminil.

Acetonitriles↗

PubMed1985

Protein metabolism in growing pigs fed corn or cassava peel based diets containing graded protein levels.

Sixty-four Large White cross Landrace weanling pigs were randomly allotted to eight treatments in a two by four factorial arrangement. The two dietary variables were cassava peel (0 and 40 per cent) and crude protein (20, 15, 10 and 5 per cent). Total serum protein concentration was significantly (P less than 0.01) reduced by protein deficiency and by its interaction with cassava peel. The multiple coefficient of determination (R2) showed that protein intake was the primary factor determining changes in serum protein. R2 values for cyanide intake (independent variable) on serum protein (dependent variable) increased from day 30 to 90 of the trial. Serum urea was increased on the 5 per cent protein diets on days 60 and 90 of the trial. The R2 values for cyanide and protein intake on serum urea concentration increased from day 30 to day 90 of the trial. Serum creatinine increased (P less than 0.05) on the 5 per cent protein diet on day 90 of the trial. The R2 value for the effects of protein intake on serum creatinine was higher than for cyanide intake on days 30 and 90. The results confirm the progressive and pronounced effects of long term cyanide intake on serum nitrogenous metabolites in pigs consuming between 110 and 120 ppm hydrocyanic acid, especially in diets containing 10 per cent or less protein.

Animals↗

PubMed1983

Effects of herbicides on the concentration of poisonous compounds in plants: a review.

Herbicides may raise, lower, or not affect the concentration of poisonous compounds in plants. Herbicides, 2,4,5-T and silvex controlled Wasatch milkvetch (Astragalus miser var oblongifolius) and markedly reduced the concentration of miserotoxin, a poisonous aliphatic nitro compound. The concentration of phototoxic furocoumarins in the leaves of spring parsley (Cymopterus watsonii) decreased to nontoxic concentrations 4 to 5 weeks after treatment with 2,4-D. The hydrocyanic acid content of wild cherry (Prunus spp) decreased after treatment with 2,4-D and 2,4,5-T, but increased in Sudangrass (Sorghum halapense) after treatment with 2,4-D. The alkaloid concentration in Barbey larkspur (Delphinium barbeyi) increased after treatment with 2,4,5-T or silvex, decreased in horsetail (Equisetum palustre) after treatment with MCPA, and was unaffected in Datura after treatment with several herbicides. The effect of herbicides on nitrate concentration in plants was dependent upon the species of plant and the herbicide used.

Alkaloids↗