56-88-2

White Crystalline Solid

Intermediate in transsulfuration whereby the mammal transfers the sulfur of methionine via homocysteine to cysteine

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.

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.

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.

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.]

[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