Decarboxylation Of Amino Acids Research Articles

Biogenic Amine Formation in Fresh Vacuum-Packaged Beef Stored at −2°C and 2°C for 100 Days

When fresh, vacuum-packaged, meat products are stored for extended periods of time, undesirable changes, due to naturally occurring microbial flora present during packaging occur. Lactobacillus spp. are known to form amines through the decarboxylation of free amino acids. Tyramine and histamine can cause intoxication in individuals taking monoamine oxidase-inhibiting drugs. This study determined 1) the effect of storage temperature on bacterial growth and biogenic amine production in vacuum-packaged beef subprimals, 2) the effect of washing subprimals with water to remove tyramine contamination, and 3) the penetration of tyramine from the surface of the subprimal.Inside rounds were vacuum packaged and stored at −2°C or 2°C. Samples were evaluated over 100 days for amine concentrations, total psychrotrophic counts and lactic acid bacteria. Tyramine, putrescine and cadaverine were detected in this study. Significant levels (15 μg/g) of tyramine were detected at 20 days of storage at 2°C and 40 days of storage at −2°C. Putrescine and cadaverine were detected first at 40 days of storage at 2°C and 60 days of storage at −2°C. Both treatment groups contained about 130 μg/g of tyramine at 100 days of storage. Psychrotrophic plate counts and lactic acid bacteria counts were initially 103 colony forming units (CFU)/cm2 and ranged from 106–107 CFU/cm2 at 100 days of storage. Even though tyramine was evident at a depth of 6 mm from the surface of the cut, one-third of the amine was removed by washing the subprimal with tap water.

Chapter 28 Trace amines in hepatic encephalopathy

In 1971 Fischer and Baldessarini proposed the hypothesis that hepatic encephalopathy (HE), a neuropsychiatric syndrome associated with hepatic dysfunction, could result from the direct decarboxylation of amino acids leading to trace amines such as tyramine and octopamine which could then act as false neurotransmitters. This was supported by the observation that the clinical symptoms of HE appeared to improve following treatment with L-Dopa, which cannot be metabolized to either of these trace amines. In addition to serum and urine levels of octopamine correlating roughly with the grade of clinical HE, levels of octopamine were also significantly increased in rat brain following coma induced by hepatic devascularization and in portacaval-shunted rats fed high aromatic amino acid content diets. This hypothesis was questioned, however, given the lack of observable adverse behavioural effects following treatments with octopamine. Finally, the equivocal results of a limited number of clinical trials (using L-Dopa) argued against a direct intervention by catecholamine-like trace amines in HE. An alternative hypothesis was advanced by Sourkes in 1978 implicating increased tryptophan metabolism as a factor in the etiology of HE. Hepatic dysfunction in humans alters CNS concentrations of tryptophan which correlate well with levels of the tryptamine metabolite indoleacetic acid (IAA). Furthermore, regional densities of [3H]tryptamine receptors in HE patient brain tissue are significantly decreased. These data support a pathophysiologic role for tryptophan and its neuroactive trace amine metabolite tryptamine in HE.

Generation of a proton motive force by histidine decarboxylation and electrogenic histidine/histamine antiport in Lactobacillus buchneri

Lactobacillus buchneri ST2A vigorously decarboxylates histidine to the biogenic amine histamine, which is excreted into the medium. Cells grown in the presence of histidine generate both a transmembrane pH gradient, inside alkaline, and an electrical potential (delta psi), inside negative, upon addition of histidine. Studies of the mechanism of histidine uptake and histamine excretion in membrane vesicles and proteoliposomes devoid of cytosolic histidine decarboxylase activity demonstrate that histidine uptake, histamine efflux, and histidine/histamine exchange are electrogenic processes. Histidine/histamine exchange is much faster than the unidirectional fluxes of these substrates, is inhibited by an inside-negative delta psi and is stimulated by an inside positive delta psi. These data suggest that the generation of metabolic energy from histidine decarboxylation results from an electrogenic histidine/histamine exchange and indirect proton extrusion due to the combined action of the decarboxylase and carrier-mediated exchange. The abundance of amino acid decarboxylation reactions among bacteria suggests that this mechanism of metabolic energy generation and/or pH regulation is widespread.

Enhanced Mineralization of Amino Acids by Birnessite as Influenced by Pyrogallol

The structural differences among amino acids influencing mineralization by soil minerals, and the role of phenols in this mineralization, is very important in C turnover and N and S transformations in soil. The objective of this study was thus to investigate the effect of birnessite and pyrogallol on the mineralization of amino acids. Using a specially designed reaction flask, amounts and distribution of CO₂ and NH₃ released were determined during 90-h reaction periods. The results show that birnessite enhanced the decarboxylation of amino acids. The amount of CO₂ released with l-serine, l-phenylalanine, l-proline, dl-methionine, and l-cysteine without birnessite was not detectable, while with birnessite-amino acid, losses were 109 ± 0, 162 ± 3, 145 ± 2, 95 ± 2, and 182 ± 3 µmol, respectively. Since L-cysteine has the strongest reducing power among the amino acids examined, the amount of CO₂ released with birnessite-l-cysteine was greatest. Birnessite enhanced the deamination of amino acids. The amounts of NH₃ released with l-serine, l-phenylalanine, l-proline, dl-methionine, and l-cysteine without birnessite were not detectable, while those with birnessite-amino acid were 140 ± 4, 145 ± 5, 66 ± 6, 83 ± 2, and 226 ± 8 µmol, respectively. Birnessite enhanced the mineralization of methionine and cysteine to release SO²⁻₄ in the supernatants of the reaction systems. The amounts of SO²⁻₄ released with dl-methionine and l-cysteine without birnessite were 0.1 ± 0.0 and 0.2 ± 0.0 µmol, respectively, while those with birnessite-amino acid were 0.8 ± 0.0 and 112 ± 7 µmol, respectively. In conclusion, the enhancing effects of birnessite play an important role in C turnover and N and S transformations in soil.

Silver(I)/peroxydisulfate-induced oxidative decarboxylation of amino acids. A chemical model for a possible intermediate in the monoamine oxidase-catalyzed oxidation of amines

Silver(I)/peroxydisulfate-induced oxidative decarboxylation of amino acids. A chemical model for a possible intermediate in the monoamine oxidase-catalyzed oxidation of amines

Postneonatal Vitamin B6-Dependent Epilepsy

Vitamin B6 acts as coenzyme in decarboxylation and transamination of amino acids. Pyridoxal phosphate is the coenzyme for a glutamic decarboxylase and γ-aminobutyric acid transaminase, enzymes necessary in production and metabolism of brain γ-aminobutyric acid. Vitamin B6 deficiency has been known to produce peripheral neuritis, dermatitis, anemia, and convulsions in infants.1 Administration of isonicotinic acid hydrazide may produce a vitamin B6-responsive neuropathy. Convulsions from vitamin B6 dependency occur despite normal vitamin B6 levels. These seizures, according to pediatric and neurological texts, occur immediately after birth up to 6 months.1-4 In 1985, Goutieres and Aicardi5 described three patients with atypical pyridoxine-dependent seizures with onset at 7 weeks, 5 days, and 4 months.

Effect of alpha-ketoacid dehydrogenase phosphorylation on branched-chain amino acid metabolism in muscle

The regulation of leucine and valine metabolism was evaluated in skeletal muscle of perfused rat hindlimb. Control of the branched-chain alpha-ketoacid dehydrogenase (BCKADH) via phosphorylation was removed with 0.4 mM alpha-chloroisocaproate (CIC). CIC activated the BCKADH complex 13- to 26-fold and led to increased rates of leucine and valine uptake into muscle, transamination to the corresponding alpha-ketoacid, and leucine (3- to 4-fold) and valine (6-fold) decarboxylation but led to decreased rates of alpha-ketoacid efflux from muscle. Although the increased rates of branched-chain amino acid (BCAA) decarboxylation were extensive, they were far below the extent of BCKADH activation as measured in vitro, suggesting that factors other than BCKADH activation become dominant in controlling the flux through alpha-ketoacid decarboxylation in skeletal muscle in situ. When the BCKADH capacity of muscle was increased 70-90% by a training-induced increase in mitochondrial content, the same 13- to 26-fold activation of the complex by CIC led to a rate of BCAA decarboxylation, which was only marginally greater (10-20%; P less than 0.05) than that of normal muscle. In addition, increasing the energy demand via muscle contractions led to a significant increase in leucine decarboxylation in the presence of complete activation of BCKADH by dephosphorylation. Thus BCKADH phosphorylation-dephosphorylation plays an important though not exclusive role in modulating the rates of BCAA metabolism in skeletal muscle. Differences in valine and leucine metabolism were apparent as valine catabolism bolstered citric acid cycle contents by increasing malate in red muscle with high mitochondrial content.(ABSTRACT TRUNCATED AT 250 WORDS)

ChemInform Abstract: ×OH Radical Induced Decarboxylation of Amino Acids. Decarboxylation vs Bond Formation in Radical Intermediates.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Catalysis of Nontronite in Phenols and Glycine Transformations

AbstractThe catalytic power of Ca-nontronite (0.2–2 μm) for the polycondensation of phenols and glycine and the associated reactions that involve the ring cleavage of phenols and the decarboxylation and deamination of glycine was studied in systems free of microbial activity. At the end of a 90-hr reaction period, the amount of CO2 released from the Ca-nontronite-glycine-pyrogallol, Ca-nontronite-glycine-eatechol, and Ca-nontronite-glycine-hydroquinone systems were 5.1, 8.7, and 11.6 times higher, respectively, than those from the respective nontronite-free systems, showing the catalytic role of Ca-nontronite in the ring cleavage of phenols and the decarboxylation of glycine. The release of CO2 and NH3 from the Ca-nontronite-glycine system revealed that Ca-nontronite can catalyze decarboxylation and deamination of glycine. The ability of Ca-nontronite to catalyze the deamination of glycine was substantially enhanced by the presence of a phenol. The visible absorbances at both 472 and 664 nm of the supernatants, the total yields of N-containing humic polymers, and the fractions of glycine converted to nitrogenous polymers indicated that polycondensation of glycine and phenol was greatly catalyzed by Ca-nontronite. The total N-containing humic polymers formed in the systems decreased in the order: Ca-nontronite-glycine-pyrogallol > Ca-nontronite-glycine-cateehol > Ca-nontronite-glycine-hydroquinone > glycine-pyrogallol > glycine-hydroquinone > glycine-catechol. The infrared and electron spin resonance spectra of humic acid (HA) and fulvic acid (FA) formed in the supernatants of the reaction systems were quite similar to those of soil HA and FA. The catalytic power of Ca-nontronite in affecting the ring cleavage of phenols, deamination and decarboxylation of amino acids, and formation of humic substances derived from phenols with amino acids in soils and the related environments thus merits attention.

Hydroxyl radical induced decarboxylation of amino acids. Decarboxylation vs bond formation in radical intermediates

The •OH radical reaction with exo-2-amino-endo-6-(methylthio)bicyclo[2.2.1]heptane-endo-2-carboxylic acid primarily affords oxidation of the sulfur center in the molecule. The subsequent pathway strongly depends on pH. A transient radical with interaction between the sulfur and the carboxylate moieties is stabilized particularly in acid solutions with maximum yield at pH 3. The underlying mechanism is considered to be a concerted action involving an electron transfer from the anionic carboxylate to the oxidized sulfur atom, homolytic carbon-carboxyl bond breakage, and deprotonation of the amino group. Related studies indicate that this kind of radical-induced decarboxylation can be generalized and receives its driving force to a significant extent from the resonance stabilization of the α-amino radical remaining after CO 2 cleavage

ChemInform Abstract: Oxidative Decarboxylation of Cyclic Amino Acids and Dehydrogenation of Cyclic Secondary Amines with Iodosobenzene.

AbstractL‐Proline (Ia) and pipecolic acid (Ib) are decarboxylated upon treatment with 2.2 equivalents of iodosobenzene, producing the lactams (II).

Application of a novel radioimmunoassay for serotonin in the detection of aromatic l-amino acid decarboxylase activity in isolated renal cortical cells

The decarboxylation of amino acids is an cssential step in the biosynthesis of biogenic amines; the enzyme aromatic Lamino acid decarboxylase (AAAD; EC 4.1.1.28) catalyses the decarboxylation of both ~-3,4-dihydroxyphenylalanine and L-5-hydroxytryptophan (5-HTP) to form dopamine or serotonin (5-HT), respectively. The AAAD enzyme is present in many tissues (Rahman et ul., 1 9 8 1 ), but is particularly active in the kidney, where the products of decarboxylation (i.e. dopamine and 5-HT) are thought to affect renal haemodynamics directly. Dopamine causes marked natriuresis, diuresis, and dilatation of the renal vasculature, whereas 5-HT is thought to exert opposite effects (Stier et al., 1984). Several previous studies have measured AAAD activity by incubating tissue homogenates with one of the enzyme substrates, followed either by direct measurement of the mass of product generated in the incubate, using high-pressure liquid chromatography coupled with electrochemical detection (Stier et al., 1987) or by measuring the amount of C 0 2 produced during the decarboxylation reaction (Clark et d., 1954). Both techniques are time consuming, and therefore restrict the throughput of large numbers of samples. We have used a radioimmunoassay ( M A ) for 5-HT developed in our own laboratories (Gow et al., 1987) to measure the production in vitro of 5-HT from 5-HTP by isolated rat renal cortical cells (RCC). Female Wistar rats (200-250 g) were killed by cervical dislocation and the kidneys removed immediately into icecold physiological saline. The kidneys were trimmed of fat, the capsules removed, and the cortex dissected from the medulla. Intact RCC were prepared using the collagenase digestion procedure described by Drury et ul. (1986), with modifications by Noble et al. (1988). The cells were finally resuspended in Medium 199 containing bovine serum albumin ( 2 g/l). For each experiment, aliquots (800 pl ) of a freshly prepared RCC suspension containing 0.5 x 1 O6 cells/ml were dispensed in duplicate into glass tubes in an ice/water slurry (4C), followed by Medium 199 (100 pl) containing both pargyline (final concentration 1 W 6 mol/l), and varying doses of 5-HTP ( O l O s mol/l, final concentration). A further aliquot of Medium 199 (100 p l ) or, for the inhibitor experiments, Medium 199 containing the AAAD inhibitor carbidopa (100 pl; lo-' mol/l, final concentration) was added, and the tubes incubated in a shaking water-bath (120 cycles/min) at 37°C for 30 min. The reaction was stopped by plunging the incubation tubes into an ice/water slurry, followed by centrifugation at 1720 g for 20 min at 4°C. The supernatants were then collected, and frozen at 20°C until analysis by RIA. Our results (Fig. 1) show a dose-dependent production of 5-HT by RCC in response to the increasing concentration of substrate (5-HTP). This response was significantly diminished ( P < 0.05, 2-way analysis of variance) by the inclusion of carbidopa ( lo- mol/l) in the incubates and is in agreement with the observations of Stier & ltskovitz (1985).

Oxidative decarboxylation of amino acids by plant extracts

Oxidative decarboxylation of amino acids by plant extracts

Immunocytochemical localization of aromatic L-amino acid decarboxylase in human, rat, and mouse bronchopulmonary and gastrointestinal endocrine cells.

Aromatic L-amino acid decarboxylase (AADC) catalyzes the cellular decarboxylation of L-aromatic amino acids and is therefore involved in the synthesis of several biogenic amines. Application of the indirect immunoperoxidase method on human, rat, and mouse tissues using specific antibodies to AADC revealed all AADC-containing cells. Besides mast cells and adrenergic nerve fibers, the following cells were immunostained: neuroendocrine cells in the tracheobronchial epithelium; neuroepithelial bodies in the bronchopulmonary epithelium; Kultschitzky cells in the small intestine and appendix as well as adrenal chromaffin cells. All the latter cells belong to the so-called APUD system, the "D" in the acronym standing for the activity of the enzyme aromatic L-amino acid decarboxylase. Immunocytochemistry for AADC may become an additional tool not only to highlight APUD cells in tissue sections but also to differentiate the sites of cellular amine synthesis from those of amine storage.

Oxidative decarboxylation of cyclic amino acids and dehydrogenation of cyclic secondary amines with iodosobenzene

Cyclic amino acids L-proline, pipecolinic acid and L-2-pyrrolidinone-5-carboxylic acid undergo oxidative decarboxylation with iodosobenzene in various solvents (including water) to yield the lactam and imide in the latter case. The reaction proceeds via initial imine formation.

Polyamine contents and amino acid decarboxylation activities of extremely halophilic archaebacteria and some eubacteria

An extremely halophilic archaebacterium Halobacterium cutirubrum was demonstrated to be devoid of any polyamine except agmatine when grown in a synthetic medium with no exogenous polyamines. Decarboxylation activities of homoarginine and canavanine as well as of arginine were shown to be present in cell lysates of 5 strains of extreme halophiles examined. H. halobium R1 was shown to have an additional pathway to synthesize agmatine from glutamic acid.

Polyamine contents and amino acid decarboxylation activities of extremely halophilic archaebacteria and some eubacteria

Polyamine contents and amino acid decarboxylation activities of extremely halophilic archaebacteria and some eubacteria

Kinetics of Oxidative Decarboxylation of Amino Acids by Bromamine-T in Alkaline Medium

Kinetics of Oxidative Decarboxylation of Amino Acids by Bromamine-T in Alkaline Medium

SPOILAGE OF ANCHOVY‐STUFFED OLIVES BY HETEROFERMENTATIVE LACTOBACILLI1

ABSTRACTAn unusual type of spoilage was encountered in canned green olives stuffed with anchovies. The spoilage was characterized by a gradual decrease in acidity of the olive brine from about pH 4.3 to 5.25 and a swelling of the cans caused by CO2. Spoilage of the product was caused by decomposition of the anchovies by proteolytic enzyme action, with subsequent decarboxylation and deamination of amino acids from the anchovies by heterofermentative lactobacilli. This type of spoilage, known as “protein swells”, occurs with canned fish marinades but, to our knowledge, does not occur with other acidified canned foods.

Polycondensation of pyrogallol and glycine and the associated reactions as catalyzed by birnessite

Birnessite catalyzes the polycondensation of pyrogallol and glycine and the subsequent formation of N-polymers which resemble natural humic substances in IR and ESR spectra. The data also reveal that birnessite promotes the deamination and decarboxylation of glycine. The catalytic power of birnessite in the polycondensation of phenols and amino acids and the subsequent formation of humic polymers in soils thus merits attention. Deamination and decarboxylation of amino acids as catalyzed by birnessite may be a new pathway of C turnover and N transformation. Mineralization of N via abiotic processes thus should not be overlooked. Furthermore, oxygen molecules play a vital role in these catalytic reactions.