Cytosolic β-glucosidase (hCBG) is a xenobiotic-metabolizing enzyme that hydrolyzes some flavonoid glucosides. This type of enzymes plays a role in metabolic detoxification, with a series of enzymatic reactions that neutralize and solubilize toxins, and then transport them to the secretory organs. Flavonoid glycocides are a family of molecules in which a sugar is linked to another functional group via a glycosidic bond and play numerous roles in living organisms, mainly in plants. Since hCBG can cleave glycosidic bonds, it is important that this enzyme does not cleave bonds that do not originate from xenobiotics, so this article studies the substrate preference of hCBG with flavonoid glycosides and, therefore, the specificity of the enzyme in based on the aglycone portion, the type of sugar and the bond between them. Glycoside hydrolases are classified into 108 families according to amino acid sequence similarities. One of these families is GH1 (Glycoside Hydrolases 1), this family is composed of enzymes with various substrate specificities and the enzymes are present in bacteria, Archaea and Eukaryotes. The 3D structure of 18 of these enzymes has been determined, and although the extent of sequence varies between 17% and 45%, all enzymes have a common 8-barrel motif (β/α) and two catalytic glutamate residues located at the C-terminal end of β-strands 4 and 7, which may provide a clue to the mechanism of these enzymes. Human cytosolic β-glucosidase is a GH1 enzyme and is present in the liver, kidney, intestine, and spleen. It has the same 8-barrel fold (β/α) characteristic of GH1 β-glucosidades, and the primarily structural differences between hCBG and other GH1 enzymes are limited primarily to the loop regions. Does not contain...... half of the card...... the crystal has been rotated 120° with a oscillation interval of 0.5° per frame. Table 1. Data collection and refinement statistics for and incubated with shaking to induce expression for crystallographic analysis of native hCBG data. Values ​​in parentheses refer to the bin with the highest resolution, 2.85–2.70 Å. Amino acid composition Ala (A) 33 7.0% Arg (R) 15 3.2% Asn (N) 18 3.8% Asp (D) 32 6.8%Cys (C) 6 1.3%Gln (Q) ) 25 5.3%Glu (E) 26 5.5%Gly (G) 34 7.2%His (H) 10 2.1%Ile (I) 27 5.8%Leu (L) 37 7.9 %Lys (K) 31 6.6%Met (M) 6 1.3%Phe (F) 31 6.6%Pro (P) 24 5.1%Ser (S) 27 5.8%Thr (T) 24 5.1%Trp (W) 15 3.2%Tyr (Y) 24 5.1%Val (V) 24 5.1%Total number of negatively charged residues (Asp + Glu): 58Total number of positively charged residues (Arg + Lys): theoretical 46PI: 5.39