catabolism

Bilirubin (Principal bile pigment) is a type of bile pigment, which is a metabolite of hemoglobin in the blood. Bilirubin has antimutagenic and antioxidant effects. Bilirubin is an important basis for clinical determination of jaundice, and is also an important indicator of liver function.

Urea (Carbonyldiamide) is formed in the liver from ammonia produced by the deamination of amino acids. It is the principal end metabolite of protein catabolism and accounts for about one-half of the total urinary solids.

Pyridoxal phosphate (Vitamin B6 phosphate) is the active form of vitamin B6 and a coenzyme for many pyridoxal phosphate (PLP)-dependent enzymes. PLP is involved in numerous enzymatic transamination, decarboxylation and deamination reactions; it is necessary for the synthesis of amino acids and amino acid metabolites, and for the synthesis and or catabolism of certain neurotransmitters, including the conversion of glutamate into gamma-aminobutyric acid (GABA) and levodopa into dopamine. PLP can be used as a dietary supplement in cases of vitamin B6 deficiency. Reduced levels of PLP in the brain can cause neurological dysfunction.

L-Citrulline, an amino acid, is derived from ornithine during the catabolism of proline, glutamate, or glutamine, and also from L-arginine via the arginine-citrulline pathway.

Methylguanidine (MG) is a guanidine compound deriving from protein catabolism. It is also a product of putrefaction. Methylguanidine is a suspected uraemic toxin that accumulates in renal failure, however it also exhibits anti-inflammatory effects. Methyl

N-acetyl-L-methionine is nutritionally and metabolically equivalent to L-methionine. Methionine is a dietary indispensable amino acid required for normal growth and development of humans, other mammals, and avian species. In addition to being a substrate

3-Methyladipic acid is a metabolite of the catabolism of phytanic acid. Patients with adult Refsums disease (ARD) are unable to detoxify phytanic acid by alpha-oxidation, and so the w-oxidation pathway is the only metabolic pathway available for phytanic

Sodium taurocholate (Taurocholate Sodium) hydrate is the main end product of cholesterol catabolism. During enterohepatic circulation, bile taurocholic acid is converted by the microorganisms to taurodeoxycholic acid and deoxycholic acid.[3] These are reabsorbed by the liver via a carrier-mediated process and converted by liver enzymes to taurocholic acid.

Phenylalanylalanine (H-Phe-Ala-OH) is a dipeptide composed of phenylalanine and alanine, produced during incomplete protein digestion or catabolism [1].

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).

(S)-β-aminoisobutyric acid is a non-protein amino acid derived from the catabolism of valine and thymine.

Isovalerylcarnitine (3-methylbutyrylcarnitine) is a small molecule compound produced by the catabolism of L-leucine and the accumulation of isovaleric acid. Isovalerylcarnitine is also a selective and effective calpain activator that can promote cell apoptosis. Isovalerylcarnitine is related to isovaleric acidemia and can be used as a marker of isovaleric acidemia.

Glycyltyrosine, a dipeptide composed of tyrosine and glycine, is an incomplete breakdown product of protein catabolism or protein digestion.

Bile acids are essential for solubilization and transport of dietary lipids, are the major products of cholesterol catabolism, and are physiological ligands for farnesoid X receptor (FXR), a nuclear receptor that regulates genes involved in lipid metabolism.1They are also inherently cytotoxic, as physiological imbalance contributes to increased oxidative stress.2,3Bile acid-controlled signaling pathways are promising novel targets to treat such metabolic diseases as obesity, type II diabetes, hyperlipidemia, and atherosclerosis.Guggulsterone, derived from resin of the guggul tree, is a competitive antagonist of FXR bothin vitroandin vivo.4Thecisstereoisomer of guggulsterone, (E)-guggulsterone, decreases chenodeoxycholic acid (CDCA)-induced FXR activation with an IC50value of 15 μM.5,6By inhibiting CDCA-induced transactivation of FXR, guggulsterone lowers low-density lipoprotein cholesterol and triglyceride levels in rodents fed a high cholesterol diet.4 1.Makishima, M., Okamoto, A.Y., Repa, J.J., et al.Identification of a nuclear receptor for bile acidsScience2841362-1365(1999) 2.Barbier, O., Torra, I.P., Sirvent, A., et al.FXR induces the UGT2B4 enzyme in hepatocytes: A potential mechanism of negative feedback control of FXR activityGastroenterology1241926-1940(2003) 3.Tan, K.P., Yang, M., and Ito, S.Activation of nuclear factor (erythroid-2 like) factor 2 by toxic bile acids provokes adaptive defense responses to enhance cell survival at the emergence of oxidative stressMol. Pharmacol.72(5)1380-1390(2007) 4.Urizar, N.L., Liverman, A.B., Dodds, D.T., et al.A natural product that lowers cholesterol as an anatagonist ligand for FXRScience296(5573)1703-1706(2002) 5.Cui, J., Huang, L., Zhao, A., et al.Guggulsterone is a farnesoid X receptor antagonist in coactivator association assays but acts to enhance transcription of bile salt export pumpThe Journal of Biological Chemisty278(12)10214-10220(2003) 6.Wu, J., Xia, C., Meier, J., et al.The hypolipidemic natural product guggulsterone acts as an antagonist of the bile acid receptorMolecular Endocrinology16(7)1590-1597(2002)

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.

5-aminovalerate (or 5-aminopentanoic acid) is a lysine degradation product. It can be produced both endogenously or through bacterial catabolism of lysine. 5-aminovalerate is formed via the following multi-step reaction: L-lysine leads to cadverine leads

Glycyl-L-valine, a dipeptide composed of glycine and valine, is an incomplete breakdown product of protein digestion or protein catabolism (incomplete breakdown product of protein digestion or protein catabolism).

3-Hydroxyisovalerylcarnitine is a carnitine derivative that may serve as a novel biomarker for biotin deficiency in humans, with its concentration increasing in such conditions. Biotin deficiency reduces the activity of biotin-dependent 3-methylcrotonyl-CoA carboxylase, hindering the conversion of 3-methylcrotonyl-CoA into 3-methylglutaconyl-CoA, and impairing the leucine catabolism pathway, resulting in elevated plasma 3-Hydroxyisovalerylcarnitine concentrations [1].