Abstract
Lactase was purified from suckling rat jejunal mucosa and the properties were investigated. Lactase of suckling rat jejunum was purified from papain-solubilized jejunal mucosa by the gel filtration (Sepharose 2B, Sephadex G-200) and the chromatography (DEAE-cellulose). The lactase obtained showed a single band in polyacrylamide gel flectrophoresis. The optimum pH of the purified lactase was 5.7. Km value of the enzyme for lactose was 12.9 mM. The purified lactase was completely inactivated by heating at 58°C for 10 min in 0.1 M sodium maleate buffer, pH 6.0. The molecular weight of the purified lactase was estimated to be 280, 000 by polyacrylamide gel electrophoresis in sodium dodecyl sulphate and 360, 000 in Sepharose 2B column chromatography.
