Taurine is conjugated via its amino terminal group with the bile acids chenodeoxycholic acid and cholic acid to form the bile salts sodium taurochenodeoxycholate and sodium taurocholate. The low pKa (1.5) of taurine's sulfonic acid group ensures that this moiety is negatively charged in the pH ranges normally found in the intestinal tract and thus improves the surfactant properties of the cholic acid conjugate. Taurine has also been implicated in a wide array of other physiological phenomena including inhibitory neurotransmission, long-term potentiation in the striatum/hippocampus, membrane stabilization, feedback inhibition of neutrophil/macrophage respiratory bursts, adipose tissue regulation and calcium homeostasis. The evidence for these claims, when compared against that reported for taurine's role in bile acid synthesis and osmoregulation, is relatively poor. Premature born infants who lack the enzymes needed to convert cystathione to cysteine may become deficient in taurine. Thus, taurine is a dietary essential nutrient in these individuals. Many therapeutic applications of taurine have been investigated. Some conditions that taurine might be useful in treating include: cardiovascular diseases, hypercholesterolemia, epilepsy and other seizure disorders, macular degeneration, Alzheimer's disease, hepatic disorders, alcoholism, and cystic fibrosis. Recent studies show that taurine supplements taken by mice on a high-fat diet reduced their overall weight. Studies have yet to be done on the effect of taurine on obesity in humans.