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At least 163 records · Page 9Linked to original sources

PubMed1981

Chelation in metal intoxication XI: effect of thiol chelators on lead poisoned rabbits.

Potentials of 2,3 Dimercapto succinic acid (DMS) and D-Penicillamine, the currently acclaimed heavy metal chelating drugs, to enhance urinary excretion of lead and restore altered levels of urinary delta-amino-levulinic acid (delta-ALA) and blood lead, -zinc-protoporphyrin (ZPP) -delta-aminolevulinic acid dehydratase (delta-ALA-D) in lead poisoned rabbits, were compared. The better performance of DMS than D-Penicillamine has been attributed to two -SH groups as a stronger metal binding site in DMS molecule.

Aminolevulinic Acid↗

PubMed2005

Stereoselective syntheses of dihydroxerulin and xerulinic acid, anti-hypocholesterolemic dyes from the fungus Xerula melanotricha.

The title compounds 2 and 3, which are inhibitors of the biosynthesis of cholesterol, were synthesized in a convergent and perfectly stereoselective manner. In the key step, bromobutenolide 6 (obtained from levulinic acid in two steps) was coupled with either of the novel bis(stannanes) trans,cis,trans-35 or trans,trans,trans-35 [each accessible from 3-(tributylstannyl)allyl alcohol (17) in four steps], giving gamma-alkylidenebutenolide trans,trans,trans-32. This compound was coupled with iododiyne 42 or the bromoenediynoate 44 leading to dihydroxerulin (2) and to the (trimethylsilylethyl)ester 45 of xerulinic acid, respectively. Deprotection of the latter provided totally synthetic xerulinic acid (3) for the first time.

Agaricales↗

PubMed1976

[Letter: Porphyria cutanea tarda: normalization of porphyrin-excretion following treatment with p-amino-benzoic acid (Potaba) (author's transl)].

Two patients with porphyria cutanea tarda were treated with p-amino-benzoic acid (Potaba) (3x4g/day). Normalization of porphyrin-excretion was observed after three respectively 45 days of treatment. Furthermore no influence of the excretion of porphyrin precursors (porphobilinogen or delta-amino-levulinic acid) were noticed. Also, no side effects of this treatment were found.

Adult↗

PubMed1978

Chloroplast culture: the chlorophyll repair potential of mature chloroplasts incubated in a simple medium.

The chlorophyll repair potential of mature Cucumis chloroplasts incubated in a simple Tris-HCl/sucrose medium is described. The chloroplasts were isolated from green, fully expanded Cucumis cotyledons which were capable of chlorophyll repair. This was evidenced by a functional chlorophyll biosynthetic pathway in the mature tissue. The biosynthesis of protocholorphyllide from exogenous delta-aminolevulinic acid was used as a marker for the operation of the chlorophyll biosynthetic chain between delta-aminolevulinic acid and protochlorophyllide. The conversion of exogenous protochlorophyllide into chlorophyll a was used as a marker for the operation of the chlorophyll pathway beyond protochlorophyllide. It appeared from these studies that contrary to published reports, unfortified fully developed Cucumis chloroplasts incubated in Tris-HCl/sucrose without the addition of cofactors exhibited a partial and limited chlorophyll repair capability. Their net tetrapyrrole biosynthetic competence from delta-aminolevulinic acid was confined to the accumulation of coproporphyrin. No net tetrapyrrole biosynthesis beyond coproporphyrin was observed. However, the plastids were capable of incorporating small amounts of delta-amino[4-(14)C]levulinic acid into [14C]protochlorophyllide but were incapable of converting exogenous protochlorophyllide into chlorophyll. After prolonged incubation of the unfortified chloroplasts in the dark, a fluorescent protochlorophyllide-like compound accumulated. This compound [Cp (E430-F631) was shown to be neither protochlorophyllide nor zinc-prototochlorophyllide but and a fluorescence emission maximum at 631 nm (F631) in methanol/acetone (4 : 1, v/v). Cp(E430-F631) WAS SHOWN TO BE NEITHER PROTOCHLOROPHYLLIDE NOR ZINC-PROTOTOCHLOROPHYLLIDE BUT an enzymatic degradation product of chlorophyll. The exact chemical identity of this compound has not yet been determined.

Cells, Cultured↗

PubMed1987

Phytochrome Chromophore Biosynthesis : Both 5-Aminolevulinic Acid and Biliverdin Overcome Inhibition by Gabaculine in Etiolated Avena sativa L. Seedlings.

Etiolated Avena sativa L. seedlings grown in the presence of gabaculine (5-amino-1,3-cyclohexadienylcarboxylic acid) contained reduced levels of phytochrome as shown by spectrophotometric and immunochemical assays. Photochromic phytochrome levels in gabaculine-grown plants were estimated to be 20% of control plants, while immunoblot analysis showed that the phytochrome protein moiety was present at approximately 50% of control levels. Gabaculine-grown seedlings administered either 5-aminolevulinic acid or biliverdin exhibited a rapid increase of spectrophotometrically detectable phytochrome. Phytochrome concentrations estimated immunochemically did not similarly increase throughout treatment with either compound. Similar experiments with 5-amino[4-(14)C] levulinic acid showed radiolabeling of phytochrome with kinetics that paralleled the spectrally detected increase. These results are consistent with (a) the intermediacy of both 5-aminolevulinic acid and biliverdin in the biosynthetic pathway of the phytochrome chromophore and (b) the lack of coordinate regulation of chromophore and apoprotein synthesis in Avena seedlings.

Journal Article↗

PubMed1982

Chloroplast biogenesis: biosynthesis of protochlorophyll(ide) via acidic and fully esterified biosynthetic branches in higher plants.

The operation of two parallel biosynthetic pathways during the biosynthesis of the protochlorophyll(ide) pool of cucumber cotyledons was probed with the use of several [14C]tetrapyrroles in vitro. A comparison of the ratio (R) of delta-amino[14C]levulinic acid incorporation into protochlorophyllide/14C incorporation into protochlorophyllide ester with other incorporation ratios, RX, where X represents any of several [14C]tetrapyrrole substrates, allowed us to determine which exogenous 14C-labeled substrate was common precursor of protochlorophyllide and protochlorophyllide ester and which one was not. From such comparisons, a biosynthetic pathway of protochlorophyll(ide) biosynthesis is inferred. According to this pathway, protochlorophyllide is formed via an acidic (mono/dicarboxylic) biosynthetic branch, while protochlorophyllide ester is formed via a fully esterified (neutral) biosynthetic branch. The two biosynthetic branches are linked together by porphyrin ester synthetases at the level of protochlorophyllides and possibly at the level of the photoporphyrin IX and the magnesium protoporphyrin monoester pools.

Chlorophyllides↗

PubMed1991

[Porphyria induced by valproic acid: clinical case].

A 47 year-old woman with juvenile myoclonic epilepsy received anticonvulsant therapy with valproate, 200 mg 4 times a day. Severe abdominal pain and vomiting developed 3 days after initiation of therapy, and she became comatose requiring artificial ventilation. Increased urinary output of delta-amino-levulinic acid (48 uM/24 hr, 8 times normal) and porphobilinogen (9 uM/24 hr, twice normal) were demonstrated. Complete recovery took place 5 days after discontinuation of valproate.

Female↗

PubMed1983

Uroporphyrinogen III, an intermediate in the biosynthesis of the nickel-containing factor F430 in Methanobacterium thermoautotrophicum.

Factor F430 is a nickel-containing porphinoid present in methanogenic bacteria. The synthesis of this nickel tetrapyrrole from 5-aminolevulinic acid was studied in Methanobacterium thermoautotrophicum. This anaerobic archaebacterium was found to accumulate [14C]uroporphyrinogen III (1.8 mumol/g) when growing on nickel-free medium (less than 50 nmol/l) supplemented with 2 mM 5-amino-[14C]levulinic acid. The accumulated urophorphyrinogen III was quantitatively converted to factor F430 when the cells were incubated in aminolevulinate-free medium with 5 microM NiCl2. The newly synthesized factor had the same specific radioactivity as the precursor uroporphyrinogen III. These findings indicate that the nickelporphinoid is biosynthetically derived from uroporphyrinogen III. The presence and some properties of the enzymes catalyzing the synthesis of uroporphyrinogen III from 5-aminolevulinic acid in M. thermoautotrophicum are also described.

Aminolevulinic Acid↗

PubMed1985

Chlorophyll biosynthesis and assembly into chlorophyll-protein complexes in isolated developing chloroplasts.

Isolated developing plastids from greening cucumber cotyledons or from photoperiodically grown pea seedlings incorporated (14)C-labeled 5-aminolevulinic acid (ALA) into chlorophyll (Chl). Incorporation was light dependent, enhanced by S-adenosylmethionine, and linear for 1 hr. The in vitro rate of Chl synthesis from ALA was comparable to the in vivo rate of Chl accumulation. Levulinic acid and dioxoheptanoic acid strongly inhibited Chl synthesis but not plastid protein synthesis. Neither chloramphenicol nor spectinomycin affected Chl synthesis, although protein synthesis was strongly inhibited. Components of thylakoid membranes from plastids incubated with [(14)C]ALA were resolved by electrophoresis and then subjected to autoradiography. This work showed that (i) newly synthesized Chl was assembled into Chl-protein complexes and (ii) the inhibition of protein synthesis during the incubation did not alter the labeling pattern. Thus, there was no observable short-term coregulation between Chl synthesis (from ALA) and the synthesis of membrane proteins in isolated plastids.

Journal Article↗

PubMed1982

[d-Aminolevulinic acid dehydrase in germinating seeds of Pinus pinea].

The purification grade of d-aminolevulinic acid dehydrase, the specific enzyme activity, the Michaelis constant and the optimum pH are determined in extracts from embryos and endosperms of Pinus pinea seeds germinated at different stages of germination. On the other hand the influence of levulinic acid, sodium cyanide, sodium malonate, sodium arsenite and sodium azide on the activity of d-aminolevulinic acid dehydrase has also been studied.

Aminolevulinic Acid↗

PubMed1974

The Biosynthesis of delta-Aminolevulinic Acid in Higher Plants: II. Formation of C-delta-Aminolevulinic Acid from Labeled Precursors in Greening Plant Tissues.

delta-Aminolevulinic acid was accumulated by greening cucumber (Cucumis sativus L. var. Alpha green) cotyledons, barley (Hordeum sativum var. Numar) leaves, and bean (Phaseolus vulgaris L. var. Red Kidney) leaves in the presence of various (14)C-labeled precursors and levulinic acid, a competitive inhibitor of delta-aminolevulinic acid dehydrase. The radioactivity in the accumulated delta-aminolevulinic acid was measured.The most effective labeled precursors were the 5 carbon dicarboxylic compounds glutamate, glutamine, and alpha-ketoglutarate. (14)C-Labeled glycine and succinate were relatively poor. The carboxyl and the methylene carbons of glycine were incorporated into delta-aminolevulinic acid to about equal extent. The carboxyl carbon of glutamate was incorporated almost as well as the internal carbons of the same compound. These results are inconsistent with the succinyl CoA-glycine succinyl transferase (delta-aminolevulinic acid synthetase) mode of delta-aminolevulinic acid production.When the same experiments were performed on turkey blood (which, as avian blood in general, possesses delta-aminolevulinic acid synthetase), delta-aminolevulinic acid was labeled most effectively from glycine-2-(14)C, moderately well from glycine-1-(14)C and glutamate-3,4-(14)C and not at all from glutamate-1-(14)C.It appears probable that greening higher plant tissues possess an alternate route to delta-aminolevulinic acid in which the carbon skeleton of glutamate (and alpha-ketoglutarate) is incorporated intact into the first committed metabolite of the chlorophyll pathway.

Journal Article↗

PubMed1985

Total synthesis of (+/-)-11 alpha-hydroxyprogesterone by cyclization of a polyunsaturated epoxide.

The total synthesis of a typical 11-hydroxylated steroid, (+/-)-11 alpha-hydroxyprogesterone, was achieved by picric acid-catalyzed tricyclization of a polyunsaturated epoxide appropriately substituted with ketal, hydroxyl, and acetylenic units. This epoxide was prepared by a multistage sequence featuring two successive alkylations of intermediary, monocyclic sulfones. The first sulfone intermediate was obtained by means of a short sequence starting from levulinic acid and diethyl succinate and involving a selective cyclization reaction.

Cyclization↗

PubMed1981

[Influence of theophylline on hexachlorobenzene induced porphyria (author's transl)].

Administration of 0.05% hexachlorobenzene (HCB) contained in the food to female (Wistar rats over a period of 60 days induced porphyria as measured by the increased urinary porphyrin excretion. One group of the rats was additionally treated with theophylline (150 mg/kg b.w./d). The concomitant theophylline application to rats with HCB induced porphyria increased their urinary excretion of porphyrin (p less than 0,1%) and its precursors (porphobilinogen and delta-aminolevulinic acid) in comparison to the HCB controls. The HCB induced increase of the hepatic cytochrome P-450 content was prevented whereas 7-ethoxycoumarine-deethylase activity was depressed concomitantly by theophylline. p-Nitro-anisole-demethylase activity was not influenced by this treatment. It is assumed that the delta-amino-levulinic acid synthase is induced by theophylline. The different behaviour of the porphyrin excretion and the cytochrome P-450 induction during this treatment leads to the conclusion that there is no direct or causal relationship between these two biochemical processes.

Animals↗

PubMed2004

Cocrystallization of melaminium levulinate monohydrate.

Crystals of 2,4,6-triamino-1,3,5-triazin-1-ium levulinate (4-oxopentanoate) monohydrate, C(3)H(7)N(6)(+).C(5)H(7)O(3)(-).H(2)O, are formed via self-assembled hydrogen bonding by cocrystallization of melamine and levulinic acid. Two N-H.N hydrogen bonds and four N-H.O hydrogen bonds connect two melaminium entities such that each of two pairs of N-H.O bonds bridges two H atoms belonging to the amine groups of two different melaminium cations via the carbonyl O atom of one levulinate molecule.

Journal Article↗

PubMed1980

[Influence of p-amino-benzoic acid on the hexachlorobenzene induced porphyria in the rat (author's transl)].

The effect of p-amino-benzoic (PAB) acid on the experimental hexachlorobenzene (HCB) induced hepatic porphyria of female Wistar rats was determined under different conditions: Neither a simultaneous HCB-PAB application (prophylactic administration) nor the PAB application after manifestation of the HCB-porphyria (therapeutic administration) influenced significantly the excretin of urinary porphyrins or precursors (porphobilinogen or 5-amino-levulinic acid). PAB application decreased the cytochrome P-450 content in the liver of the rats whereas HCB incuded enzymatic activity of this monooxygenase measured by the O-dealkylation of 7-ethoxycoumarin was not diminished by PAB application. The glycine concentration and the glycine content of rat livers were not decreased by the simultaneous HCB-PAB treatment in contrast to PAB controls. These findings are discussed and the conclusion is drawn that there might be different types of human porphyria cutanea tarda. The predominently exogenously induced PCT in men and the HCB induced porphyria in rats cannot be influenced by PAB application.

4-Aminobenzoic Acid↗

PubMed1998

Fluorescence detection of flat transitional cell carcinoma after intravesical instillation of aminolevulinic acid.

Carcinoma in situ (CIS) of the bladder is a confounding disease that is difficult to recognize endoscopically because it is a flat cancer. Many studies have suggested its relationship with subsequent invasive disease. Early recognition of CIS therefore is essential in offering the patient the most appropriate treatment and the highest cure rate. Because white light cystoscopic examination is not sufficient to reveal areas of dysplasia or CIS, random biopsies are recommended. The authors evaluate whether amino levulinic acid (ALA) fluorescence detection could be helpful in diagnosing CIS and if the specificity could be enhanced by reducing the ALA dose. Sixteen patients with papillary bladder cancer, and CIS and dysplasia were given low-dose ALA. Fluorescence detection of the metabolized ALA was performed 3 hours later, with the naked eye, after blue light illumination. Carcinoma in situ or dysplasia was found in 50 biopsies. The sensitivity for detecting CIS was 94% with a specificity of 54%. Carcinoma in situ can be diagnosed with a very high accuracy through fluorescence detection after ALA instillation. Fluorescence detection can be achieved with the naked eye and does not necessitate either complex equipment or specially trained personnel.

Administration, Intravesical↗

PubMed1991

Effect of alcohol on delta-aminolevulinic acid dehydratase and porphyrin metabolism in man.

The influence of alcohol on porphyrin metabolism was investigated in 6 healthy non-alcoholics and 19 patients with chronic alcohol abuse. In the healthy subjects, blood and urine samples were obtained before and after acute alcohol exposure, whereas in the chronic alcoholics only one examination was performed. In both groups a significant inhibition of delta-aminolevulinic acid dehydratase was demonstrated. The activity was partially restored in vitro by addition of zinc ions or dithiothreitol. A combination of both activators produced reactivation to normal levels. Coproporphyrinuria was more prominent in chronic alcoholics (373 nmol/24 h on average, upper norm 119 nmol/24 h) compared to non-alcoholics (140 nmol/24 h). Urinary porphobilinogen and delta-amino-levulinic acid were normal except for a moderately increased delta-aminolevulinic acid in four healthy individuals. In conclusion, alcohol causes reversible inhibition of delta-aminolevulinic acid dehydratase. The metabolic changes reflect both an inhibition of delta-aminolevulinic acid dehydratase and coproporphyrinogen oxidase; a simultaneous, moderate induction of hepatic delta-aminolevulinic acid synthase is suggested. Erythrocyte delta-aminolevulinic acid dehydratase activity could serve as a sensitive indicator for both acute and chronic alcohol consumption even better than coproporphyrinuria.

Adult↗

PubMed1991

Renal heme metabolism in hereditary tyrosinemia: use of succinylacetone in rat renal tubules.

Succinylacetone (SA), a metabolic end-product found in urine from individuals with hereditary tyrosinemia and associated renal Fanconi syndrome and a known inhibitor of hepatic 5-aminolevulinic acid dehydratase (ALAD), has been used to study heme metabolism in isolated rat renal tubules. Heme biosynthetic porphyrin precursors are increased selectively in the presence of 4 mmol/1 SA. Total porphyrin content of the tubules are increased approximately 2-fold, while both ferrochelatase and heme oxygenase activities remain unaffected by SA. Nonetheless, total heme content is reduced, as was incorporation of radioactive label from amino[14C]levulinic acid. Cytochrome P-450 content remained unaffected. Impairment of iron uptake and/or transport within the cell or enhancement of heme catabolism via a non-heme oxygenase-dependent pathway could explain the observations.

Amino Acid Metabolism, Inborn Errors↗