Purification and partial characterization of alpha-mannosidase from Trypanosoma rangeli

An alpha -mannosidase from Trypanosoma rangeli was partially purified by a protocol involving solubilization using lysis buffer followed by chromatogr aphy on diethylaminoethyl (DEAE)-cellulose and Sephadex 100 columns. The en zyme has a molecular weight of 45 kDa as determined by sodium dodecyl sulfa te-polyacrylamide gel electrophoresis (SDS-PAGE) and of 90 kDa as determine d by gel filtration. The purified T. rangeli alpha -mannosidase has a pH op timum ranging between 5 and 6 and a temperature optimum of 37 degreesC. It has activation energy of 8.15 x 10(2) J mol(-1) K-1. The enzyme has a Micha elis constant (K-m) of 99 muM for the 4-methylumbelliferyl-alpha -D-mannopy ranoside substrate (MU-alpha -mann). It is strongly inhibited by swainsonin e [inhibition constant (K-i) 0.048 muM] and is moderately inhibited by mann ose and alpha -D-methylmannopyranoside. The enzyme activity is decreased in the presence of 1 mM Ca2+, Co2+, Cu2+, Fe2+, Fe3+, Hg2+, Mg2+ and Mn2+.