Characterization of alpha-mannosidase from Erythrina indica seeds and influence of endogenous lectin on its activity.

alpha-mannosidase from Erythrina indica seeds is a Zn(2+) dependent glycoprotein with 8.6% carbohydrate. The enzyme has a temperature optimum of 50 degrees C and energy of activation calculated from Arrhenius plot was found to be 23 kJ mol(-1). N-terminal sequence up to five amino acid residues was found to be DTQEN (Asp, Thr, Gln, Glu, and Asn). In chemical modification studies treatment of the enzyme with NBS led to total loss of enzyme activity and modification of a single tryptophan residue led to inactivation. Fluorescence studies over a pH range of 3-8 have shown tryptophan residue to be in highly hydrophobic environment and pH change did not bring about any appreciable change in its environment. Far-UV CD spectrum indicated predominance of alpha-helical structure in the enzyme. alpha-Mannosidase from E indica exhibits immunological identity with alpha-mannosidase from Canavalia ensiformis but not with the same enzyme from Glycine max and Cicer arietinum. Incubation of E. indica seed lectin with alpha-mannosidase resulted in 35% increase in its activity, while no such activation was observed for acid phosphatase from E. indica. Lectin induced activation of alpha-mannosidase could be completely abolished in presence of lactose, a sugar specific for lectin.

Efectos embriotoxicos de erythrina falcata benth, (familia fabaceae) / Effects embriotoxicos of erythrina falcata benth, (family fabaceae)

Erythrina falcata Benth. bark infusion at 10%, orally provided to the pregnant Albino Swiss female mice during 86 hours post-coitum (86 hpc) inhibited the formation of blastocysts, reduced the cell number and mitetic index, and increased the frecuency of micronuclei of early embryos. These results show that E. falcata induces embryotoxic effects both citological and citogenetical level.

Infusiones de la corteza de Erythrina falcata Benth, al 10% suminitrada oralmente a ratonas preñadas Albino Swiss durante 86 horas post-coitum (bpc), inhibieron la formación de blastocistos, disminuyeron el número celular e indice mitótico y aumentaron la frecuencia de micronúcleos de los embriones tempranos. Estos resultados indican que la E. falcata produce efectos embriotóxicos tanto a nivel citológico como citogenético.