Abstract
Sucrase-isomaltase complex (S-I) was purified from rat intestinal mucosa and its properties were observed in comparison with those of other species.
1. Rat intestinal S-I having maltase activity was purified from papain solubilized intestinal mucosa by the following ammonium sulfate fractionation, Sephadex G-200 column chromatography and DEAE Sephadex A-25 column chromatography.
2. The molecular weight of rat intestinal S-I was estimated as 215, 000 by polyacrylamide disc gel electrophoresis.
3. Km values of sucrase, isomaltase and maltase activities of the complex were 18.0, 4.0 and 3.7mm, respectively. These enzyme activities were competitively inhibited by Tris. Furthermore, these enzyme activities were inhibited by heavy metal ions either completely (Ag+, Hg++) or partially (Cu++, Zn++). Optimal pH was 6.0.
The properties of rat intestinal S-I were similar to those of other species.
