Home  |  Contact
PROSITE documentation PDOC00800

Homoserine dehydrogenase signature


Homoserine dehydrogenase (EC (HDh) [1,2] catalyzes NAD-dependent reduction of aspartate β-semialdehyde into homoserine. This reaction is the third step in a pathway leading from aspartate to homoserine. The latter participates in the biosynthesis of threonine and then isoleucine as well as in that of methionine.

HDh is found either as a single chain protein as in some bacteria and yeast, or as a bifunctional enzyme consisting of an N-terminal aspartokinase domain and a C-terminal HDh domain as in bacteria such as Escherichia coli and in plants.

As a signature pattern, we selected the best conserved region of Hdh. This is a segment of 23 to 24 residues located in the central section and that contains two conserved aspartate residues.

Last update:

July 1998 / Pattern and text revised.

Technical section

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

HOMOSER_DHGENASE, PS01042; Homoserine dehydrogenase signature  (PATTERN)


1AuthorsThomas D. Barbey R. Surdin-Kerjan Y.
TitleEvolutionary relationships between yeast and bacterial homoserine dehydrogenases.
SourceFEBS Lett. 323:289-293(1993).
PubMed ID8500624

2AuthorsCami B. Clepet C. Patte J.-C.
TitleEvolutionary comparisons of three enzymes of the threonine biosynthetic pathway among several microbial species.
SourceBiochimie 75:487-495(1993).
PubMed ID8395899

PROSITE is copyright. It is produced by the SIB Swiss Institute Bioinformatics. There are no restrictions on its use by non-profit institutions as long as its content is in no way modified. Usage by and for commercial entities requires a license agreement. For information about the licensing scheme send an email to
Prosite License or see: prosite_license.html.


View entry in original PROSITE document format
View entry in raw text format (no links)