PURIFICATION AND PROPERTIES OF RABBIT INTESTINAL SUCRASE

Rabbit intestinal sucrase, which is associated with the microvillous membrane of the mucosal cell, was solubilized with papain [EG 3.4.4.10] and purified by utilizing its reversible adsorption on Sephadex G-200 and gel filtration on Bio-Gel P-300.The purified enzyme was homogeneous on ultracentrifugation and disc electrophoresis analyses. The sedimentation coefficient (s20 w) of the enzyme was 10.0S and its molecular weight was estimated to be approximately 235, 000 by the Archibald method.It hydrolyzed maltose and α-methylglucoside in addition to sucrose, but not α, α-trehalose. β-Glucosides and α- and β-galactosides tested were not hydrolyzed. Melezi-tose served as a substrate but raffinose did not. Furthermore, the maltase activity present in the homogenate paralleled to the sucrase activity during purification. These findings indicate that the enzyme is a glucosido-sucrasc or an α-glucosidase [EC 3.2.1.20].Other enzymatic properties such as pH optimum, Michaelis constant, activators and inhibitors were studied. © 1969 BY THE JOURNAL OF BIOCHEMISTRY.