Hypotaurine is a sulfinic acid that is an intermediate in the biosynthesis of

taurine Taurine (), or 2-aminoethanesulfonic acid, is a naturally occurring amino sulfonic acid that is widely distributed in animal tissues. It is a major constituent of bile and can be found in the large intestine. It is named after Latin (cogna ...

. Like taurine, it also acts as an

endogenous Endogeny, in biology, refers to the property of originating or developing from within an organism, tissue, or cell. For example, ''endogenous substances'', and ''endogenous processes'' are those that originate within a living system (e.g. an ...

neurotransmitter A neurotransmitter is a signaling molecule secreted by a neuron to affect another cell across a Chemical synapse, synapse. The cell receiving the signal, or target cell, may be another neuron, but could also be a gland or muscle cell. Neurotra ...

via action on the

glycine receptor The glycine receptor (abbreviated as GlyR or GLR) is the receptor Receptor may refer to: * Sensory receptor, in physiology, any neurite structure that, on receiving environmental stimuli, produces an informative nerve impulse *Receptor (biochem ...

s. It is an osmolyte with

antioxidant Antioxidants are Chemical compound, compounds that inhibit Redox, oxidation, a chemical reaction that can produce Radical (chemistry), free radicals. Autoxidation leads to degradation of organic compounds, including living matter. Antioxidants ...

properties. Hypotaurine is derived from

cysteine Cysteine (; symbol Cys or C) is a semiessential proteinogenic amino acid with the chemical formula, formula . The thiol side chain in cysteine enables the formation of Disulfide, disulfide bonds, and often participates in enzymatic reactions as ...

(and homocysteine). In mammals, the biosynthesis of hypotaurine from cysteine occurs in the pancreas. In the

cysteine sulfinic acid Cysteine sulfinic acid is the organic compound with the nominal formula HO2SCH2CH(NH2)CO2H . It is a rare example of an amino acid bearing a sulfinic acid functional group. It is a white solid that is soluble in water. Like most natural amino acid ...

pathway,

is first oxidized to its sulfinic acid, catalyzed by the enzyme cysteine dioxygenase. Cysteine sulfinic acid, in turn, is decarboxylated by

sulfinoalanine decarboxylase The enzyme sulfinoalanine decarboxylase () catalysis, catalyzes the chemical reaction :3-sulfino-L-alanine \rightleftharpoons hypotaurine + CO2 Hence, this enzyme has one substrate (biochemistry), substrate, 3-sulfino-L-alanine (also known as C ...

to form hypotaurine. Hypotaurine is enzymatically oxidized to yield taurine by hypotaurine dehydrogenase. Degradation of Cysteine to Taurine

References

Aminoethyl compounds Sulfinic acids Glycine receptor agonists {{nervous-system-drug-stub