Jacaratia corumbensis O. Kuntze a New Vegetable Source for Milk-Clotting Enzymes

摘要

The partial characterization and purification of milk clotting enzyme obtained from the (root latex) of Jacaratia corumbensis O. kuntze was studied, by fractional precipitation with ammonium sulphate and ion exchange chromatography. The ammonium sulphate precipitate showed five fractions (AS1 - 0-20%; AS2 - 20-40%; AS3 - 40-60%; AS4 - 60-80%; AS5 - 80-100%) and among the fractions obtained, the 40-60% fraction (AS3) showed the highest milk clotting activity with a purification factor of 1.2 fold in relation to the crude extract. This fraction when applied on Mono Q column yielded two protein peaks (p1 and p2), but p1 pool showed the best milk-clotting activity. The optimal pH for the crude and partially purified extract was 6.5 and 7.0, respectively. The maximum milk-clotting activity was at 55 C for the both crude and partially purified extracts. The enzyme was inhibited by iodoacetic acid which suggested that this enzyme was a cysteine protease, with molecular weight of 33 kDa.