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Serine and threonine dehydratases [1,2] are functionally and structurally related pyridoxal-phosphate dependent enzymes:

• L-serine dehydratase (EC 4.3.1.17) and D-serine dehydratase (EC 4.3.1.18) catalyze the dehydratation of L-serine (respectively D-serine) into ammonia and pyruvate.
• Threonine dehydratase (EC 4.3.1.19) (TDH) catalyzes the dehydratation of threonine into α-ketobutarate and ammonia. In Escherichia coli and other microorganisms, two classes of TDH are known to exist. One is involved in the biosynthesis of isoleucine, the other in hydroxamino acid catabolism.

Threonine synthase (EC 4.2.3.1) is also a pyridoxal-phosphate enzyme, it catalyzes the transformation of homoserine-phosphate into threonine. It has been shown [3] that threonine synthase is distantly related to the serine/ threonine dehydratases.

In all these enzymes, the pyridoxal-phosphate group is attached to a lysine residue. The sequence around this residue is sufficiently conserved to allow the derivation of a pattern specific to serine/threonine dehydratases and threonine synthases.

Some bacterial L-serine dehydratases - such as those from Escherichia coli - are iron-sulfur proteins [4] and do not belong to this family.

December 2004 / Pattern and text revised.

PROSITE method (with tools and information) covered by this documentation:

DEHYDRATASE_SER_THR, PS00165; Serine/threonine dehydratases pyridoxal-phosphate attachment site  (PATTERN)

Consensus pattern: [DESH]-x(4,5)-[STVG]-{EVKD}-[AS]-[FYI]-K-[DLIFSA]-[RLVMF]-[GA]-[LIVMGA] The K is the pyridoxal-P attachment site Sequences known to belong to this class detected by the pattern: ALL Other sequence(s) detected in Swiss-Prot: 17.

• Retrieve an alignment of Swiss-Prot true positive hits:   Clustal format, color, condensed view  / Clustal format, color  / Clustal format, plain text  / Fasta format • Retrieve the sequence logo from the alignment • Taxonomic tree view of all Swiss-Prot/TrEMBL entries matching PS00165 • Retrieve a list of all Swiss-Prot/TrEMBL entries matching PS00165 • Scan Swiss-Prot/TrEMBL entries against PS00165 • view ligand binding statistics

Matching PDB structures: 1KL7 1P5J 1PWE 1PWH ... [ALL]

1	Authors	Ogawa H., Gomi T., Konishi K., Date T., Nakashima H., Nose K., Matsuda Y., Peraino C., Pitot H.C., Fujioka M.
	Title	Human liver serine dehydratase. cDNA cloning and sequence homology with hydroxyamino acid dehydratases from other sources.
	Source	J. Biol. Chem. 264:15818-15823(1989).
	PubMed ID	2674117

2	Authors	Datta P., Goss T.J., Omnaas J.R., Patil R.V.
	Title	Covalent structure of biodegradative threonine dehydratase of Escherichia coli: homology with other dehydratases.
	Source	Proc. Natl. Acad. Sci. U.S.A. 84:393-397(1987).
	PubMed ID	3540965

3	Authors	Parsot C.
	Title	Evolution of biosynthetic pathways: a common ancestor for threonine synthase, threonine dehydratase and D-serine dehydratase.
	Source	EMBO J. 5:3013-3019(1986).
	PubMed ID	3098560

4	Authors	Grabowski R., Hofmeister A.E.M., Buckel W.
	Title	Bacterial L-serine dehydratases: a new family of enzymes containing iron-sulfur clusters.
	Source	Trends Biochem. Sci. 18:297-300(1993).
	PubMed ID	8236444

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