Description
L-
(+)-
Cystathionine is a dipeptide formed by serine and homocysteine. Transsulfuration of methionine yields homocysteine, which combines with serine to form this precursor of cysteine. L-
(+)-
Cystathionine is largely expressed in the mammalian brain and deficiency can indicate the presence of metabolic disorders such as cystathioninuria.
Chemical Properties
White Crystalline Solid
Uses
Intermediate in transsulfuration whereby the mammal transfers the sulfur of methionine via homocysteine to cysteine
Uses
L-Cystathionine has been used in ultra-performance liquid chromatography for the validation of cystathionine and the correlation of its abundance with vertebrate metamorphosis. It has also been used as an inhibitor of sinusoidal GSH (glutathione) carrier to signify that thiol redox state imbalance is associated with the modulation of autophagy in carcinoma cells.
Definition
ChEBI: L-cystathionine is a modified amino acid generated by enzymic means from L-homocysteine and L-serine. It has a role as a human metabolite, a Saccharomyces cerevisiae metabolite, an Escherichia coli metabolite and a mouse metabolite. It is a tautomer of a L-cystathionine dizwitterion.
Biochem/physiol Actions
L-Cystathionine is an intermediate in the biosynthesis of L-cysteine and methionine. It is used as a substrate to differentiate and analyze cystathionine γ-lyase(s). L-Cystathionine is an important non-protein amino acid and is associated with metabolic disorders. In recent studies, L-cystathionine is believed to be the precursor of cyclic imino acid cyclothionine. Cystathioninuria is characterized with imino acid cyclothionine excretion in the urine.
Purification Methods
S,S-Cystathionine is purified by converting it to the HCl salt in 20% HCl and carefully basifying with aqueous NH3 until separation is complete. Filter it off and dry it in a vacuum. It forms prisms from H2O. The dibenzoyl derivative has m 229o (from EtOH). [IR: Greenstein & Winitz Chemistry of the Amino Acids (J Wiley) Vol 3 p2690 1961 and Tallan et al. J Biol Chem 230 707 1958, Synthesis: du Vigneaud et al. J Biol Chem 143 59 1942, Anslow et al. J Biol Chem 166 39 1946.] [Prepn: Weiss & Stekol J Am Chem Soc 73 2497 1951; see also du Vigneaud et al. J Biol Chem 143 60 1942, Biological synthesis: Greenberg Methods Enzymol 5 943 1962, Beilstein 4 IV 3197.]
References
[1] FINKELSTEIN J D. The metabolism of homocysteine: pathways and regulation.[J]. European Journal of Pediatrics, 1998, 157 Suppl 2: S40-4. DOI:
10.1007/pl00014300[2] TAKUYA NISHI. Accumulation of L-cystathionine by an Escherichia coli mutant deficient in cystathionine beta-lyase.[J]. Journal of bioscience and bioengineering, 2002, 94 2: 178-181. DOI:
10.1263/jbb.94.178
