Glucosidase Essay

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Cytosolic β-Glucosidase (hCBG) is a xenobiotic-metabolizing enzyme that hydrolyses certain flavonoid glucosides. This type of enzymes play a role in the metabolic detoxification, with a series of enzymatic reactions that neutralize and solubilize toxins, and then transport them to secretory organs. Flavonoid glusocides is a family of molecules in which a sugar is bound to another functional group by a glycosidic bond, and play numerous roles in living organisms, mainly in plants. Since the hCBG can cleave glycosidic bonds, is important that this enzyme does not cleave bonds that are not from xenobiotics, so this paper study the substrate preference of the hCBG with flavonoid glucosides, and thus, the specificity of the enzyme depending on the aglycone moiety, type of sugar and the linkage between them. Glycoside Hydrolases are classified into 108 families according with the amino acid sequence similarities. One of these families is GH1 (Glycoside Hydrolases 1), this family consists of enzymes with various substrate specificities, and the enzymes are present is bacteria, Archaea and Eukaryota. The 3D structure of 18 of these enzymes had been determined, and although the extent of sequence varies between 17% and 45%, all the enzymes have a common (β/α)8-barrel motif, and two catalytic glutamate residues located at the C-terminal end of β-strands 4 and 7, which may give a clue about the mechanism of these enzymes. The Human Cytosolic β-glucosidase is a GH1 enzyme and is present in the liver, kidney, intestine and spleen. It have the same (β/α)8-barrel fold characteristic of GH1 β-glucosidades, and the mainly structural differences between the hCBG and the other GH1 enzymes is confined mainly to loop regions. It does not cont... ... middle of paper ... ...e crystal was rotated through 120° with a 0.5° oscillation range per frame. Table 1. Data collection and refinement statistics for the and incubated with shaking to induce the expression for crystallographic analysis of the hCBG native data. Values in parentheses are for the highest resolution bin, 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): 58 Total number of positively charged residues (Arg + Lys): 46 Theoretical pI: 5.39

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