D Glucosidase

The common identity of human acid ]0-D-glucosidase and j3-D-xylosidase is indicated by similar binding patterns of the glycoside hydrolase activities of each enzyme to various lectins, by similar ratios between their intra- and extracellular levels in normal and I-cell fibroblasts, and by their deficiencies in liver tissues from patients with Gaucher disease, ... 

When the accessible concentration range of glycal [A] c Kj and kpg- c khydr as for ) -D-galactosidase from E. coli, this reduces to k (1 + [S]/ Kp,) = (kp /K,0 [A] + khydf. The rate constant k yj, for the addition of water has to be measured separately, by the appearance of the 2-deoxy-o-hexose. With )S-D-galactosidase from E. and yS-D-glucosidase from... 

Immobilization of (3-D-glucosidase from almonds on photo-crosslinkable resin prepolymer (ENTP-4000) was carried out by the following procedure. One gram of ENTP-4000 was mixed with 10 mg of a photosensitizer, benzoin ethyl ether, and 110 mg of (3-D-glucosidase from almonds (3.4 units mg ). The mixture was layered on a sheet of transparent polyester film (thickness, ca. 0.5 mm). The layer was covered with transparent thin film and then illuminated with chemical lamps (wavelength range 300 00 nm) for 3 min. The gel film thus obtained was cut into small pieces (0.5 x 5 x 5 mm) and used for bioconversion reaction. 

Differential scanning calorimetiy (DSC) of native and crosslinked -D-g ucosidase. The sample of glutaraldehyde-stabilized -D-glucosidase was produced essentially as detailed earlier (77), i.e., by treatment of the enzyme with glutaraldehyde at pH 9.0 in borate for... 

Crosslinking with glutaraldehyde has been shown earlier (17) to result in an 80-fold increase in half-life of the -D-glucosidase under thermal stress at (65 C) pH 5.0. 

Figure 1. pH-dependence of the half-life for loss of activity in native and glutaraldehyde-modified j9-D-glucosidase upon preincubation at the indicated pH values and at a range of temperatures from 55o to 70 oC, with subsequent assay at pH 5.0, 45 oC. A,B Linear-ordinate and logarithmic-ordinate plots, respectively, for the glutaraldehyde-modified enzyme. 

Figure 2. Comparison of DSC thermograms for native and glutaraldehyde (GA)-crosslinked / -D-glucosidase at pH 5.0 in lOmM NaCl. In order to facilitate comparison of the peaks, the differential heat capacity values plotted for the native enzyme are the actual values multiplied by a fector of 0.571.

Figure 3. Protein (upper) and activity (lower) loading of four anion exchange resins with Novozym SP188 -D-glucosidase in 10 mM sodium acetate pH 5.0. Samples were incubated for 18 h at 22 C.

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