Fumaric acid uses the fumarase enzyme to become malic acid. Malate dehydrogenase catalyzes the conversion of malic acid into oxaloacetate. Two forms of this enzyme exist in eukaryotes. One operates within the mitochondria to contribute to the Citric Acid Cycle; the other is in the cytosol where it participates in the malate/ aspartate shuttle. Riboflavin is an important cofactor for this enzyme and overall mitochondrial energy production and cellular function. At the end of each Citric Acid Cycle, the four-carbon oxaloacetate has been regenerated, and the cycle continues.

Malonic acid is found to be associated with malonyl-CoA decarboxylase deficiency, which is an inborn error of metabolism. The name “Malonic” originates from Latin malum, meaning apple. Malonic acid is the archetypal example of a competitive inhibitor: it acts against succinate dehydrogenase (complex II) in the respiratory electron transport chain. 

Malonic acid is found to be associated with malonyl-CoA decarboxylase deficiency, which is an inborn error of metabolism. The name “Malonic” originates from Latin malum, meaning apple. Malonic acid is the archetypal example of a competitive inhibitor: it acts against succinate dehydrogenase (complex II) in the respiratory electron transport chain. 

Malonic acid is found to be associated with malonyl-CoA decarboxylase deficiency, which is an inborn error of metabolism. The name “Malonic” originates from Latin malum, meaning apple. Malonic acid is the archetypal example of a competitive inhibitor: it acts against succinate dehydrogenase (complex II) in the respiratory electron transport chain. 

Mandelate is a Styrene metabolite.

Sources of exposure:

- Raw materials (benzene and ethylene) for the manufacture of styrene are supplied primarily from the petroleum industry.

- Used in the manufacture of synthetic rubbers, synthetic latex, polyesters, and plastic products.

- Automotive emissions, tobacco smoke, released from building materials, carpet backing. Low-level exposure may occure through ingestion of food products packaged in polystyrene containers.

- Packaging materials, toys, hobbies, crafts, house wares and appliances, electrical and thermal insulation, fiberglass, pipes, automobile parts, foam cups.

- Emissions from styrene production and disposal procedures - chemical spills, landfill sites and industrial discharges.

- Occupational Exposure: industries and operations concerned with the fabrication and application of plastics - styrene/polystyrene manufacturing plants, resin manufacturers, synthetic rubber plants, boats and automobile plants, laminators.

Mandelate + Phenylglyoxylate are Styrene metabolites.

Sources of exposure:

- Raw materials (benzene and ethylene) for the manufacture of styrene are supplied primarily from the petroleum industry.

- Used in the manufacture of synthetic rubbers, synthetic latex, polyesters, and plastic products.

- Automotive emissions, tobacco smoke, released from building materials, carpet backing. Low-level exposure may occure through ingestion of food products packaged in polystyrene containers.

- Packaging materials, toys, hobbies, crafts, house wares and appliances, electrical and thermal insulation, fiberglass, pipes, automobile parts, foam cups.

Mandelic acid is the major metabolite of styrene. Styrene (vinylbenzene) is used as an intermediate in plastic synthesis. Values less than 5 mg/L are due to normal metabolism of phenylalanine or tyrosine.

Mandelic acid is the major metabolite of styrene. Styrene (vinylbenzene) is used as an intermediate in plastic synthesis. Values less than 5 mg/L are due to normal metabolism of phenylalanine or tyrosine.

→ Mandelic acid and benzoylformate are major metabolites of styrene and ethylbenzene exposure.

→ Styrene is a key component in consumer products. Occupational exposure has been associated with increased rates of pulmonary, neurological, genetic, ocular, and reproductive complications, plus leukemia.

→ Styrene can be found in polystyrene packaging and can migrate into packaged food.

→ Benzoylformate has been associated with metabolism of adrenaline and noradrenaline, and phenylketonuria.

→ In a review of 2005–2006 and 2011–2012 NHANES data (N=4690), smokers had 2-fold and 1.6-fold higher levels of both markers.

→ Eating more vegetables and fruit was associated with decreased levels.

Manganese (Mn) is an essential element which is involved in the activation of many important enzymes. However, Mn excess is postulated to result in glutathionyl radical formation, reduction of the free glutathione pool, and increased exposure of adrenal catecholamines (e.g. dopamine) to free radical damage.

Hair Manganese (Mn) levels generally reflect actual body stores, and external contamination can influence hair Mn. Since particulate manganese-containing dust is the most common source of Mn toxicity, hair is considered to be an excellent tissue for the assessment of Mn exposure.

Manganese is a mineral element that is both nutritionally essential and has the potential to be very toxic. This fact is further complicated by the small range of dosage for clinical benefit and toxicity with serious consequences. Manganese is an important factor in many critical biochemical processes including antioxidant function. The principle antioxidant enzyme within our mitochondria (energy) is superoxide dismutase and the enzymes requires manganese for optimal performance. Manganese is also required for normal skeletal development and cartilage synthesis. Wound healing is also impacted by manganese, as the synthesis of collagen in skin cells is dependent on the presence of adequate manganese. Manganese is also important functioning as a co-factor in the metabolism of carbohydrates, amino acids and cholesterol. Manganese is considered anti-osteoporotic and anti-arthritic.

Manganese is a mineral that plays a key role in forming connective tissue, sex hormones, making blood clotting factors, bone health, wound healing and central nervous system function. Manganese is also essential for the absorption of calcium, as well as glucose regulation, carbohydrate, fat, cholesterol and amino acid metabolism. 

Chronic exposure to manganese (as in industrial settings) may cause effects on the central nervous system.

Toxic exposure may occur from dry cells, fungicide (maneb), and in the steel or chemical industries. Manganese is present in the coloring agents for glass and soap, in paints, varnish and enamel, and in linoleum.

It is used in the manufacturing of chlorine gas and in lead-free gasoline. Industrial manganese poisoning has been recognized since 1837.

Manganese (Mn) is an essential element which is involved in the activation of many important enzymes. However, Mn excess is postulated to result in glutathionyl radical formation, reduction of the free glutathione pool, and increased exposure of adrenal catecholamines (e.g. dopamine) to free radical damage.

Hair Manganese (Mn) levels generally reflect actual body stores, and external contamination can influence hair Mn. Since particulate manganese-containing dust is the most common source of Mn toxicity, hair is considered to be an excellent tissue for the assessment of Mn exposure.