Reactome | PXLP-CBS tetramers condenses HCYS and L-Ser to form L-Cystathionine

PXLP-CBS tetramers condenses HCYS and L-Ser to form L-Cystathionine

Stable Identifier

R-HSA-1614524

Type

Reaction [transition]

Species

Homo sapiens

Compartment

cytosol

Synonyms

L-homocysteine + L-serine => H2O + L,L-cystathionine

ReviewStatus

5/5

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PXLP-CBS tetramers condenses HCYS and L-Ser to form L-Cystathionine

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The first step of homocysteine conversion to cysteine is catalyzed by cystathionine beta-lyase, which adds a serine molecule to the substrate. The enzyme is a tetramer with two heme molecules as cofactor (Janosik et al. 2001). CBS also utilises pyridoxal 5'-phosphate (PXLP) as cofactor, at the evolutionarily conserved Lys119 residue (Kery et al. 1999). The cystathionine beta-synthase-like protein (CBSL) is thought to function like CBS.

Literature References

PubMed ID	Title	Journal	Year
10052942	Binding of pyridoxal 5'-phosphate to the heme protein human cystathionine beta-synthase Kery, V, Kraus, JP, Meyer, JD, Manning, MC, Poneleit, L	Biochemistry	1999
11524006	Regulation of human cystathionine beta-synthase by S-adenosyl-L-methionine: evidence for two catalytically active conformations involving an autoinhibitory domain in the C-terminal region Gaustadnes, M, Kraus, JP, Kery, V, Maclean, KN, Janosík, M	Biochemistry	2001