inborn

Malonic acid (propanedioic 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.

N-Acetyl-L-arginine (Ac-Arg-OH), an N-acyl-L-alpha-amino acid with a strong basic nature (based on its pKa), has elevated serum levels in hyperargininemic patients and is associated with several diseases, including uremia and colorectal cancer. In untreated hyperargininemic patients, it reaches its highest levels in cerebrospinal fluid. It has also been detected in apples and loquats, suggesting it could be a potential biomarker for consumption of these foods. Additionally, a low-arginine diet combined with sodium benzoate therapy leads to a marked decrease in plasma N-acetyl-L-arginine concentrations.

It is an isomer of cresotinic acid (2-hydroxy-3-methylbenzoic acid) and oxymethylbenzoic acid (2-methoxybenzoic acid). Derivatives of mandelic acid are formed as a result of metabolism of adrenaline and noradrenaline by monoamine oxidase and catechol-o-methyl transferase. It is also present in certain skin care products, is an intermediate molecule in the production of other biochemicals, may be used as an analytical reagent and is a precursor in the manufacture of dyes. Mandelic acid (acidomandelico) is found to be associated with phenylketonuria, which is an inborn error of metabolism.

Palmitoleic acid ((Z)-Hexadec-9-enoic acid) is found to be associated with isovaleric acidemia, which is an inborn error of metabolism.

3-Hydroxybutyric acid (Butanoic acid) (or beta-hydroxybutyrate) is a ketone body. Like the other ketone bodies (acetoacetate and acetone), levels of 3-hydroxybutyrate in blood and urine are raised in ketosis. In humans, 3-hydroxybutyrate is synthesized in the liver from acetyl-CoA and can be used as an energy source by the brain when blood glucose is low. Blood levels of 3-hydroxybutyric acid levels may be monitored in diabetic patients to look for diabetic ketoacidosis. Persistent mild hyperketonemia is a common finding in newborns. Ketone bodies serve as an indispensable source of energy for extrahepatic tissues, especially the brain and lung of developing mammals. Another important function of ketone bodies is to provide acetoacetyl-CoA and acetyl-CoA for the synthesis of cholesterol, fatty acids, and complex lipids. During the early postnatal period, acetoacetate (AcAc) and beta-hydroxybutyrate are preferred over glucose as substrates for synthesis of phospholipids and sphingolipids in accord with requirements for brain growth and myelination. Thus, during the first 2 weeks of postnatal development, when the accumulation of cholesterol and phospholipids accelerates, the proportion of ketone bodies incorporated into these lipids increases. On the other hand, an increased proportion of ketone bodies is utilized for cerebroside synthesis during the period of active myelination. In the lung, AcAc serves better than glucose as a precursor for the synthesis of lung phospholipids. The synthesized lipids, particularly dipalmitoylphosphatidylcholine, are incorporated into surfactant, and thus have a potential role in supplying adequate surfactant lipids to maintain lung function during the early days of life (PMID: 3884391 ). 3-Hydroxybutyric acid is found to be associated with fumarase deficiency and medium-chain acyl-CoA dehydrogenase deficiency, which are inborn errors of metabolism.

Methylglutaric acid is a leucine metabolite. A large amount of methylglutaric acid is identified in urine of patients with deficiency of 3-methylglutaconyl coenzyme A hydratase (PMID 6181239 ). Methylglutaric acid is also found to be associated with 3-hyd

Increased levels of erucic acid (22:1n9) have been found in the red blood cell membranes of autistic subjects with developmental regression (PMID: 16581239 ). Erucic acid (13(Z)-Docosenoic Acid) is broken down long-chain acyl-coenzyme A (CoA) dehydrogenase, which is produced in the liver. This enzyme breaks this long chain fatty acid into shorter-chain fatty acids. human infants have relatively low amounts of this enzyme and because of this, babies should not be given foods high in erucic acid. Erucic acid is found to be associated with isovaleric acidemia, which is an inborn error of metabolism.

3-Hydroxyphenylacetic acid is a rutin metabolite and an antioxidant. It has a protective biological activity in human. It is a substrate of enzyme 4-hydroxyphenylacetate 3-monooxygenase [EC 1.14.13.3] in the pathway tyrosine metabolism. 3-Hydroxyphenylace

Phenylpyruvic acid (3-Phenylpyruvic acid) is a keto-acid that is an intermediate or catabolic byproduct of phenylalanine metabolism. It has a slight honey-like odor. Levels of phenylpyruvate are normally very low in blood or urine. High levels of phenylpyruvic acid can be found in the urine of individuals with phenylketonuria (PKU), an inborn error of metabolism.

2,2-Dihydroxyacetic acid (Formylformic acid) is an intermediate in the glyoxalate cycle, which enables certain organisms to convert fatty acids to carbohydrates.2,2-Dihydroxyacetic acid has been found to be associated with primary hyperoxaluria, an inborn error of metabolism. As an aldehyde, glyoxalate is also highly active and can modify proteins to form advanced glycosylation products (AGEs).

N-Isovaleroylglycine (Isovaleroylglycine) is an acyl glycine. Acyl glycines are normally minor metabolites of fatty acids. However, the excretion of certain acyl glycines is increased in several inborn errors of metabolism. In certain cases, the measurement of these metabolites in body fluids can be used to diagnose disorders associated with mitochondrial fatty acid beta-oxidation. Acyl glycines are produced through the action of glycine N-acyltransferase which is an enzyme that catalyzes the chemical reaction: acyl-CoA + glycine < -- > CoA + N-acylglycine. N-Isovaleroylglycine is a byproduct of the catabolism of the amino acid leucine. Accumulation of N-Isovaleroylglycine occurs in Isovaleric Acidemia (IVA).

3-Methylhistidine belongs to the class of organic compounds known as histidine and derivatives. Histidine and derivatives are compounds containing cysteine or a derivative thereof resulting from reaction of cysteine at the amino group or the carboxy group

3-Amino-2-methylpropanoic acid (α-Methyl-β-alanine) is the product from the conversion of N-carbamyl-beta-aminoisobutyric acid by the enzyme Beta-ureidopropionase (EC 3.5.1.6), the last step in pyrimidine degradation. Beta-ureidopropionase deficiency is an inborn error of pyrimidine degradation associated with neurological abnormalities.

N-(3-Phenylpropionyl)glycine (Phenylpropionylglycine) is an acyl glycine. Acyl glycines are normally minor metabolites of fatty acids. However, the excretion of certain acyl glycines is increased in several inborn errors of metabolism. Acyl glycines are produced through the action of glycine N-acyltransferase which is an enzyme that catalyzes the chemical reaction:acyl-CoA + glycine < - > CoA + N-acylglycineThe detection of phenylpropionylglycine in urine after an oral load of phenylpropionic acid can be used to diagnose deficiency of medium-chain acyl-CoA dehydrogenase, a frequent and treatable metabolic defect.

4-Hydroxyphenylpyruvic acid is an enzyme inhibitor.4-Hydroxyphenylpyruvic acid (4-HPPA) is a keto acid that is involved in the tyrosine catabolism pathway. It is a product of the enzyme (R)-4-hydroxyphenyllactate dehydrogenase (EC 1.1.1.222) and is formed during tyrosine metabolism. The conversion from tyrosine to 4-HPPA is catalyzed by tyrosine aminotransferase. Additionally, 4-HPPA can be converted to homogentisic acid which is one of the precursors to ochronotic pigment. The enzyme 4-hydroxyphenylpyruvic acid dioxygenase (HPD) catalyzes the reaction that converts 4-hydroxyphenylpyruvic acid to homogentisic acid. A deficiency in the catalytic activity of HPD is known to lead to tyrosinemia type III, an autosomal recessive disorder characterized by elevated levels of blood tyrosine and massive excretion of tyrosine derivatives into urine. It has been shown that hawkinsinuria, an autosomal dominant disorder characterized by the excretion of 'hawkinsin,' may also be a result of HPD deficiency . Moreover, 4-hydroxyphenylpyruvic acid is also found to be associated in phenylketonuria, which is also an inborn error of metabolism. There are two isomers of HPPA, specifically 4HPPA and 3HPPA, of which 4HPPA is the most common.