PROSITE documentation PDOC00495
Glycosyl hydrolases family 1 signatures


It has been shown [1,2,3,4] that the following glycosyl hydrolases can be, on the basis of sequence similarities, classified into a single family:

  • β-glucosidases (EC from various bacteria such as Agrobacterium strain ATCC 21400, Bacillus polymyxa, and Caldocellum saccharolyticum.
  • Two plants (clover) β-glucosidases (EC
  • Two different β-galactosidases (EC from the archaebacteria Sulfolobus solfataricus (genes bgaS and lacS).
  • 6-phospho-β-galactosidases (EC from various bacteria such as Lactobacillus casei, Lactococcus lactis, and Staphylococcus aureus.
  • 6-phospho-β-glucosidases (EC from Escherichia coli (genes bglB and ascB) and from Erwinia chrysanthemi (gene arbB).
  • Plants myrosinases (EC (sinigrinase) (thioglucosidase).
  • Mammalian lactase-phlorizin hydrolase (LPH) (EC / EC LPH, an integral membrane glycoprotein, is the enzyme that splits lactose in the small intestine. LPH is a large protein of about 1900 residues which contains four tandem repeats of a domain of about 450 residues which is evolutionary related to the above glycosyl hydrolases.

One of the conserved regions in these enzymes is centered on a conserved glutamic acid residue which has been shown [5], in the β-glucosidase from Agrobacterium, to be directly involved in glycosidic bond cleavage by acting as a nucleophile. We have used this region as a signature pattern. As a second signature pattern we selected a conserved region, found in the N-terminal extremity of these enzymes, this region also contains a glutamic acid residue.


This pattern will pick up the last two domains of LPH; the first two domains, which are removed from the LPH precursor by proteolytic processing, have lost the active site glutamate and may therefore be inactive [4].

Consensus pattern:

F-x-[FYWM]-[GSTA]-x-[GSTA]-x-[GSTA](2)-[FYNH]-[NQ]-x-E-x- [GSTA]

Sequences known to belong to this class detected by the pattern:


Other sequence(s) detected in Swiss-Prot:



This pattern will pick up the last three domains of LPH.

Expert(s) to contact by email:

Henrissat B.

Last update:

November 1995 / Patterns and text revised.


Technical section

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

GLYCOSYL_HYDROL_F1_1, PS00572; Glycosyl hydrolases family 1 active site  (PATTERN)

GLYCOSYL_HYDROL_F1_2, PS00653; Glycosyl hydrolases family 1 N-terminal signature  (PATTERN)


1AuthorsHenrissat B.
TitleA classification of glycosyl hydrolases based on amino acid sequence similarities.
SourceBiochem. J. 280:309-316(1991).
PubMed ID1747104

2AuthorsHenrissat B.
TitleSequence homology between a beta-galactosidase and some beta-glucosidases.
SourceProtein Seq. Data Anal. 4:61-62(1991).
PubMed ID1924272

3AuthorsGonzalez-Candelas L. Ramon D. Polaina J.
SourceGene 95:31-38(1990).

4AuthorsEl Hassouni M. Henrissat B. Chippaux M. Barras F.
SourceJ. Bacteriol. 174:765-777(1992).

5AuthorsWithers S.G. Warren R.A.J. Street I.P. Rupitz K. Kempton J.B. Aebersold R.
SourceJ. Am. Chem. Soc. 112:5887-5889(1990).

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