Expression of Recombinant\nHuman α‑Glucosidase\nin HEK293 Cells

In mammals, intestinal α-glucosidase exists as\na maltase–glucoamylase\ncomplex (MGAM) and a sucrase–isomaltase complex (SI). In this\nstudy, we transiently expressed human MGAM and SI in human embryonic\nkidney 293 (HEK293) cells. At pH 6.0 and 37 °C, the MGAM-expressing\nHEK293 cells extract (MGE) exhibited maltase, glucoamylase, and isomaltase\nactivities but not sucrase activity, whereas the SI-expressing HEK293\ncells extract (SIE) exhibited sucrase, isomaltase, and maltase activities\nbut not glucoamylase activity. The apparent <i>K</i><sub>m</sub> value of the MGE for maltose hydrolysis was 14–26%\nof that of the SIE for maltose, sucrose, and isomaltose hydrolysis.\nThe respective apparent <i>V</i><sub>max</sub> values of\nthe MGE and SIE for sucrose and isomaltose hydrolysis were 0% and\n6% and 10% and 42% of those for maltose hydrolysis. These results\nindicated that the maltase activities of MGAM and SI were higher than\nthose of sucrase and isomaltase.