β-Glucosidases.
β-Glucosidases (3.2.1.21) are found in all domains of living organisms, where they play essential roles in the removal of nonreducing terminal glucosyl residues from saccharides and glycosides. β-Glucosidases function in glycolipid and exogenous glycoside metabolism in animals, defense, cell wall lignification, cell wall β-glucan turnover, phytohormone activation, and release of aromatic compounds in plants, and biomass conversion in microorganisms. These functions lead to many agricultural and industrial applications. β-Glucosidases have been classified into glycoside hydrolase (GH) families GH1, GH3, GH5, GH9, and GH30, based on their amino acid sequences, while other β-glucosidases remain to be classified. The GH1, GH5, and GH30 β-glucosidases fall in GH Clan A, which consists of proteins with (β/α)(8)-barrel structures. In contrast, the active site of GH3 enzymes comprises two domains, while GH9 enzymes have (α/α)(6) barrel structures. The mechanism by which GH1 enzymes recognize and hydrolyze substrates with different specificities remains an area of intense study.
Ketudat Cairns
James R
JR
Schools of Biochemistry and Chemistry, Institute of Science, Suranaree University of Technology, 111 University Avenue, Muang District, Nakhon Ratchasima, Thailand. cairns@sut.ac.th
Esen
Asim
A
D000818:Animals; D020134:Catalytic Domain; D044602:Cellulases / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D013379:Substrate Specificity
D044602:Cellulases