Taurineconjugated

Taurine-conjugated, in the context of biochemistry and physiology, refers to molecules that carry a taurine moiety, most commonly bile acids linked to taurine to form bile salts. In many mammals, hepatocytes conjugate primary bile acids with either glycine or taurine; the taurine-conjugated forms are typically called tauro- conjugates, such as taurocholic acid and related compounds.

Conjugation is catalyzed by the enzyme bile acid-CoA:amino acid N-acyltransferase (BAAT) in hepatocytes, forming an amide bond between the bile acid carboxyl group and taurine. The major tauro-conjugated bile acids are taurocholic acid (TCA), taurochenodeoxycholic acid (TCDCA), taurodeoxycholic acid (TDCA), tauroursodeoxycholic acid (TUDCA), and taurolithocholic acid (TLCA). After secretion into bile and release into the intestine, these salts emulsify fats; in the gut they can be deconjugated by bacterial enzymes and occasionally reconjugated in the liver.

The presence of taurine increases the hydrophilicity and ionization of these bile acids, enhancing solubility and supporting enterohepatic circulation and micelle formation. Taurine-conjugated bile acids can activate bile acid receptors such as FXR and TGR5, influencing lipid, glucose, and energy metabolism; differences between taurine and glycine conjugates affect their intestinal handling and microbial metabolism.

Alterations in taurine-conjugated bile acids occur in liver disease and cholestasis and can be detected in serum or bile, informing metabolomic studies. Therapeutically, taurine-conjugated forms such as tauroursodeoxycholic acid (TUDCA) have been investigated for hepatoprotective and neuroprotective effects, and taurine conjugation remains a focus in bile acid biology.