Characterization of partially purified α-glucosidase in the insoluble fraction of bovine crystalline lens

DOI: 10.1248/bpb.18.1133

Source and publish data:

Biological and Pharmaceutical Bulletin p. 1133 - 1137 (1995)

Update date:2022-08-16

Topics:

Authors:

Kamei Kamei

Fujiyama

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Article abstract of DOI:10.1248/bpb.18.1133

Two fractions of neutral α-glucosidase were partially purified from the insoluble fraction of bovine lens. This is the first report of such an event to the best of our knowledge. The apparent native molecular weights of these fractions were 121 kDa (fraction-I) and 254 kDa (fraction-II). Both fractions contained three polypeptides with molecular weights of 21, 25 and 30 kDa, although the proportion of these peptides was different in both fractions. The optimal pH of fraction-I and fraction-II was pH 6.0 and 6.5, and the optimal temperature for both fractions was approximately 50°C. The K(m) values of fractions-I and -II for 4-methylumbelliferyl-α-glucopyranoside were 0.086, and 0.192 mM. The activities of these enzymes were inhibited strongly by HgCl₂ and slightly by D-iodoacetic acid, but not by D-turanose. From this, we suggest that the enzyme in the insoluble fraction of bovine lens may he a cytoplasmic neutral α-glucosidase which binds to the cell membrane.