Binding Site

Cysteine synthase/cystathionine beta-synthase, pyridoxal-phosphate attachment site (IPR001216)

Short name: P-phosphate_BS


Cysteine synthase (EC: (CSase) is the enzyme responsible for the formation of cysteine from O-acetyl-serine and hydrogen sulphide with the concomitant release of acetic acid [PMID: 8344414]. In bacteria such as Escherichia coli, two such forms of the enzyme are known (genes cysK and cysM). In plants there are also two forms, one located in the cytoplasm and the other in chloroplasts.

Cystathionine beta-synthase (EC: catalyses the first irreversible step in homocysteine transulphuration, the conjugation of homocysteine and serine forming cystathionine. Like Csase it is a pyridoxal-phosphate dependent enzyme [PMID: 1597473].

Both enzymes are evolutionary related. The pyridoxal-phosphate attaches to the lysine residue found in the N-terminal section of these enzymes; the sequence around the lysine residue is highly conserved.

GO terms

Biological Process

GO:0006535 cysteine biosynthetic process from serine

Molecular Function

No terms assigned in this category.

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
PROSITE patterns