Abstract δ-Aminolevulinic Acid Research Articles

Chloroplast biogenesis 91: Detection of δ-aminolevulinic acid esterases activity in higher plant and insect tissues

δ-Aminolevulinic acid (ALA) esterase(s) is an enzyme or a family of enzymes that regenerate ALA from ALA esters by hydrolysis. These enzyme(s) are highly active in cancer cells. As a consequence ALA esters have been used to advantage in ALA-dependent photoradiation therapy, since ALA esters translocate better to sites of metabolism in cancer cells and tissues than free ALA. In this work, it is shown that ALA esterase(s) also occur in insect and plant tissues, but are less active than in cancer cells. In plant cells ALA esterase activity is observed in the cytosol as well as in the plastids where most of the activity is observed in the plastid stoma. The ALA esterase activity appears to be sensitive to the nature of the esterifying alcohol as well as to components of the incubation medium. The observed lower activity of ALA ester conversion to tetrapyrroles in insect and plant cells, in comparison to free ALA, suggests that the use of ALA esters in photodynamic insecticidal and herbicidal applications may not be as advantageous as their use in cancer photodynamic therapy treatments. It is proposed that ALA esterase(s) may be involved in the mobilization of sequestered and esterified ALA. Esterification and sequestering of excess ALA may be visualized as a mean of cellular detoxification.

Melatonin Protects Against Oxidative Stress Caused by δ-Aminolevulinic Acid: Implications for Cancer Reduction

δ-Aminolevulinic acid (ALA) is a precursor of haem. The increased concentration of ALA is typically related to acute intermittent porphyria, hereditary tyrosinemia, and lead poisoning. δ-Aminolevulinic acid produced in excess accumulates in a number of organs, causes oxidative damage, and often leads to cancer. Melatonin (N-acetyl-5-methoxytryptamine) is a well-known antioxidant, free radical scavenger, and exhibits anticarcinogenic properties. It protects DNA, lipids, and proteins from oxidative damage. The protective effects of melatonin against ALA-induced oxidation of guanine bases, lipid peroxidation, and alterations in membrane fluidity in several organs have been documented. There is an inverse relationship between melatonin and ALA concentrations in both experimental and clinical conditions of porphyria. The marked efficacy of melatonin in protecting against ALA-related oxidative stress, its oncostatic properties, and low toxicity constitute reasons to consider the use of this indoleamine as a co-treatment in patients suffering from disturbances related to ALA accumulation.

Erythrocyte δ-Aminolevulinic Acid Dehydratase (ALAD) Activity as an Indicator of Lead Exposure in Dogs and Cats: Optimal Test Conditions

δ-Aminolevulinic acid dehydratase (ALAD) activity is a very sensitive indicator of lead exposure. The purpose of this study was to determine the optimal pH, aminolevulinic acid (ALA) concentration, and incubation time for running the assay in both dogs and cats. Lead was added as lead chloride in vitro to the blood of dogs and cats that had not been exposed to lead. The assay was performed with use of a standardized procedure for humans. The activity levels ranged from 103 to 380 nM porphobilinogen formed per ml of erythrocytes per hour (PBG/ml RBC/h) in dogs, and from 105 to 387 nM PBG/ml RBC/h in cats, depending upon the concentration of lead in the blood. There was a strong negative exponential relationship between the blood lead concentration and the ALAD activity. The optimal conditions appeared to be pH 6.4, incubation time ≥ 30 minutes, and concentration of ALA in the buffer solution ≥ 0.005 M. These conditions are equivalent to those described for the assay in humans.

Purification and Properties of Solubilized Mitochondrial δ-Aminolevulinic Acid Synthetase and Comparison with the Cytosol Enzyme

Abstract δ-Aminolevulinic acid synthetase extracted from porphyric liver mitochondria by sonication or freeze-drying was found to be excluded from Sephadex G-200, and other studies revealed that activity was associated with a large aggregate. In contrast, aminoacetone synthetase behaved as a soluble enzyme with a molecular weight of 64,000. By treating the aggregate with both sodium chloride and dithioerythritol, δ-aminolevulinic acid synthetase activity was released to yield a soluble form of enzyme of molecular weight 77,000, as determined by Sephadex gel chromatography. This form of the enzyme was purified 40-fold from rat liver mitochondria by a method involving affinity chromatography. Antibodies prepared against the purified mitochondrial enzyme cross-react with the cytosol enzyme, although Sephadex chromatography indicates its molecular weight to be 178,000. No enzymically inactive, immunologically reactive precursor of δ-aminolevulinic acid synthetase could be detected in normal rat liver. End product inhibition by hemin was found to be 50% at 10 µm.

Diagnosis of a Case of Acute Intermittent Porphyria with the Aid of Thin-Layer Chromatography—Thin-Layer Electrophoresis of Urine

Abstract δ-Aminolevulinic acid and porphobilinogen were identified in urine from a patient with acute intermittent porphyria on routine amino acid chromatography. The compounds were well and rapidly separated by a two-dimensional combination of high-voltage, thin-layer electrophoresis and chromatography. Both compounds gave a yellowish color with ninhydrin; the porphobilinogen gave a strong red color when Ehrlich’s reagent was then applied. Such a pattern has not been observed in any blood and urinary amino acid chromatograms from over 900 patients with other conditions, who were receiving a variety of drugs. We consider this a rapid, specific diagnostic aid in cases of acute intermittent porphyria.