The ESTHER server presents information on all alpha/beta hydrolase fold proteins, and it focuses on a smaller group of proteins of the superfamily for which sequence homology can be detected.
This group of sequences includes cholinesterases, carboxylesterases, lipases, and some non enzymatic domains of other proteins.
The sequence homologies of these subtypes suggests that they derive from a common ancestor. Although some sequences show little homology, some blocks are conserved.These blocks were used to select sequences for the ESTHER database.

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