RESUMO
A beta-glucosidase with high specificity for podophyllotoxin-4-O-beta-D-glucopyranoside was purified from the leaves of Podophyllum peltatum. The 65-kDa polypeptide had optimum activity at pH 5.0 and was essentially inactive at pH 6.5 or above. Maximum catalytic activity of this glucosidase was obtained at 45 degrees C, but the enzyme was not heat stable. This beta-glucosidase displayed higher substrate specificity for podophyllotoxin-4-O-beta-D-glucopyranoside than for the other lignans tested, and for the (1-->3) linkage of laminaribiose than for other glucosidic linkages.
Assuntos
Glucosídeos/metabolismo , Podofilotoxina/análogos & derivados , Podofilotoxina/metabolismo , Podophyllum peltatum/enzimologia , beta-Glucosidase/metabolismo , Dissacarídeos/química , Dissacarídeos/metabolismo , Estabilidade Enzimática , Glucosídeos/química , Concentração de Íons de Hidrogênio , Estrutura Molecular , Folhas de Planta/enzimologia , Podofilotoxina/química , Especificidade por Substrato , Temperatura , beta-Glucosidase/química , beta-Glucosidase/isolamento & purificaçãoRESUMO
In an effort to develop a sustainable source of podophyllotoxin for the production of anticancer drugs such as etoposide, teniposide and etopophos, Podophyllum peltatum accessions with podophyllotoxin-rich leaf biomass were identified and transplanted to different growing conditions by vegetative cuttings. Results indicate that the lignan profile in leaves does not change over time or due to environment conditions. Podophyllotoxin and alpha-peltatin content in the blades seems to be stable with an inverse relationship of concentration between these compounds. A podophyllotoxin-rich leaf accession showed low biosynthetic capability to synthesize alpha- and beta-peltatin and the converse was also true, indicating that selection and cultivation of high-yielding podophyllotoxin leaf biomass may reduce production costs.
