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PROSITE documentation PDOC00787

Glycosyl hydrolases family 39 putative active site


It has been shown [1,E1] that the following glycosyl hydrolases can be classified into a single family on the basis of sequence similarities:

  • Mammalian lysosomal α-L-iduronidase (EC
  • Caldocellum saccharolyticum and Thermoanaerobacter saccharolyticum β- xylosidase (EC (gene xynB).

The best conserved regions in these enzymes is located in the N-terminal section. It contains a glutamic acid residue which, on the basis of similarities with other families of glycosyl hydrolases [2], probably acts as the proton donor in the catalytic mechanism. We use this region as a signature pattern.

Expert(s) to contact by email:

Henrissat B.

Last update:

May 2004 / Text revised.

Technical section

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

GLYCOSYL_HYDROL_F39, PS01027; Glycosyl hydrolases family 39 active site  (PATTERN)


1AuthorsHenrissat B., Bairoch A.
TitleNew families in the classification of glycosyl hydrolases based on amino acid sequence similarities.
SourceBiochem. J. 293:781-788(1993).
PubMed ID8352747

2AuthorsHenrissat B., Callebaut I., Fabrega S., Lehn P., Mornon J.-P., Davies G.
TitleConserved catalytic machinery and the prediction of a common fold for several families of glycosyl hydrolases.
SourceProc. Natl. Acad. Sci. U.S.A. 92:7090-7094(1995).
PubMed ID7624375


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